全文获取类型
收费全文 | 17513篇 |
免费 | 303篇 |
专业分类
各国政治 | 886篇 |
工人农民 | 1397篇 |
世界政治 | 924篇 |
外交国际关系 | 683篇 |
法律 | 9905篇 |
中国共产党 | 2篇 |
中国政治 | 161篇 |
政治理论 | 3765篇 |
综合类 | 93篇 |
出版年
2020年 | 125篇 |
2019年 | 161篇 |
2018年 | 1431篇 |
2017年 | 1405篇 |
2016年 | 1228篇 |
2015年 | 267篇 |
2014年 | 229篇 |
2013年 | 1247篇 |
2012年 | 424篇 |
2011年 | 1216篇 |
2010年 | 1203篇 |
2009年 | 808篇 |
2008年 | 969篇 |
2007年 | 895篇 |
2006年 | 243篇 |
2005年 | 262篇 |
2004年 | 396篇 |
2003年 | 383篇 |
2002年 | 211篇 |
2001年 | 367篇 |
2000年 | 345篇 |
1999年 | 301篇 |
1998年 | 161篇 |
1997年 | 117篇 |
1996年 | 132篇 |
1995年 | 128篇 |
1994年 | 137篇 |
1993年 | 105篇 |
1992年 | 167篇 |
1991年 | 161篇 |
1990年 | 151篇 |
1989年 | 143篇 |
1988年 | 160篇 |
1987年 | 164篇 |
1986年 | 162篇 |
1985年 | 149篇 |
1984年 | 158篇 |
1983年 | 165篇 |
1982年 | 100篇 |
1981年 | 71篇 |
1980年 | 82篇 |
1979年 | 107篇 |
1978年 | 87篇 |
1977年 | 76篇 |
1976年 | 68篇 |
1975年 | 60篇 |
1973年 | 50篇 |
1972年 | 57篇 |
1971年 | 56篇 |
1969年 | 55篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Yoshino M Taniguchi M Imaizumi K Miyasaka S Tanijiri T Yano H David C Thomas L Clement JG 《Forensic science international》2005,148(2-3):113-120
A new retrieval system for a 3D facial image database was designed and its reliability was experimentally examined. This system has two steps, firstly to automatically adjust the orientation of all 3D facial images in a database to that of the 2D facial image of a target person, and then to identify the facial image of the target person from the adjusted 3D facial images in the database using a graph-matching method. From the experimental study [M. Yoshino, K. Imaizumi, T. Tanijiri, J.G. Clement, Automatic adjustment of facial orientation in 3D face image database, Jpn. J. Sci. Tech. Iden. 8 (2003) 41-47], it is concluded that the software developed for the first step will be applicable to the automatic adjustment of facial orientation in the 3D facial image database. In 28 out of 110 sets (25.5%), the 3D image of the target person was chosen as the best match (from a database of 132 3D facial images) according to the similarity of the facial image characteristics based on the graph matching. The 3D facial image of the target person was ranked in the top of 10 of the database in 75 out of 110 sets (68.2%). These results suggest that this system is inadequate for the identification level, but may be feasible for screening method in a small database. It will be necessary to further pursue the possibility of realization of a facial image retrieval system for a large database such as suspects' facial images in future. 相似文献
992.
The use of coxal elements for age and sex diagnosis from the skeleton is the primary and most widespread way of bringing us closer to the identity of dead individuals in archaeological and certain forensic scenarios. Diagnosis in sub-adults, especially in fetus and infant age, is not clear; and further studies are needed. This work presents the analysis of the growth of six variables in the ilium, from birth to 97 years of age, in order to evaluate its significance and its capacity for age and sex determination during and after growth. The materials used were 327 specimens from four documented Western European collections. Growth curves were calculated for the three classical variables of the ilium (width, length and index) and three new variables of the acetabulum area (horizontal and vertical diameter of the ilium acetabular surface and the ilium acetabular index). None of the curves showed a lineal growth, except those of the horizontal diameter of the ilium acetabular surface for the male series. The ilium width has the most complicated growth and it is explained by a four-degree polynomial. All the variables studied can be useful for adult sex discrimination with the exception of the ilium width and ilium acetabular index. Furthermore, the most useful variables for subadult and adult age estimation in archaeological samples, as well as in forensic samples, are the absolute measurements (ilium length and width, horizontal and vertical diameter of the ilium acetabular surface); however, the ilium width is the best variable, as this can be applied to all growth ages using both sexual series together up to 20 years of age. 相似文献
993.
The bodies of socially isolated people may remain undiscovered in their own houses for prolonged periods. Occasionally the body is in situ for sufficient time to become skeletonised, or partially so. Medico-legal investigation of these cases is complicated by degradation and contamination of evidence. Thus, a multidisciplinary forensic investigation is recommended. The potential contributions of forensic pathology, anthropology, odontology and entomology are outlined here with reference to two cases that occurred in Victoria, Australia, in 2003. Forensic pathologists are often unable to determine the cause of death in skeletonised bodies, however, they may find evidence to support either a natural or unnatural mode of death, and they may describe skeletal pathology or trauma, and identify skeletal features to support radiological identification of the deceased. Anthropologists can provide supplementary evidence of skeletal trauma. Additionally, they can assess age, sex, stature and racial affiliation from skeletal remains. Odontologists can identify individuals through comparison with ante-mortem dental records; however, potential difficulties exist in identifying the treating dentist of a socially isolated person. Odontologists may also examine the teeth and oro-facial skeleton for trauma. Entomologists may estimate minimum death time and/or season of death. Entomological examination of insect remains may also confirm that a body has lain in situ for a considerable period. 相似文献
994.
Cherni L Pereira L Goios A Loueslati BY Khodjet el Khil H Gomes I Gusmão L Alves C Slama A Amorim A Elgaaied AB 《Forensic science international》2005,152(1):95-99
The 11 Y-chromosomal short tandem repeats (STRs) included in the Promega Corporation PowerPlex Y System (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438 and DYS439) were typed in three ethnic groups ("Andalusians", Berber and Arab) and one cosmopolitan population (Tunis) from Tunisia, summing up 247 individuals, and 139 different haplotypes. Focusing the analysis on the seven Y-STRs of the YHRD Minimal Haplotype Core (DYS385 excepted), "Andalusians" showed no differences from the Cosmopolitan and the Arab samples previously published (our Arab sample presented an extremely low haplotype diversity), but were different from the Berbers. The Berbers from Tunisia were not different from those from Morocco. 相似文献
995.
Salas A Prieto L Montesino M Albarrán C Arroyo E Paredes-Herrera MR Di Lonardo AM Doutremepuich C Fernández-Fernández I de la Vega AG Alves C López CM López-Soto M Lorente JA Picornell A Espinheira RM Hernández A Palacio AM Espinoza M Yunis JJ Pérez-Lezaun A Pestano JJ Carril JC Corach D Vide MC Alvarez-Iglesias V Pinheiro MF Whittle MR Brehm A Gómez J 《Forensic science international》2005,150(2-3):191-198
A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu. 相似文献
996.
Validation of a 21-locus autosomal SNP multiplex for forensic identification purposes 总被引:8,自引:0,他引:8
Dixon LA Murray CM Archer EJ Dobbins AE Koumi P Gill P 《Forensic science international》2005,154(1):62-77
A single nucleotide polymorphism (SNP) multiplex has been developed to analyse highly degraded and low copy number (LCN) DNA template, i.e. <100 pg, for scenarios including mass disaster identification. The multiplex consists of 20 autosomal non-coding loci plus Amelogenin for sex determination, amplified in a single tube PCR reaction and visualised on the Applied Biosystems 3100 capillary electrophoresis (CE) system. Allele-specific primers tailed with shared universal tag sequences were designed to speed multiplex design and balance the amplification efficiencies of all loci through the use of a single reverse and two differentially labelled allele denoting forward universal primers. As the multiplex is intended for use with samples too degraded for conventional profiling, a computer program was specifically developed to aid interpretation. Critical factors taken into account by the software include empirically determined extremes of heterozygous imbalance (Hb) and the drop-out threshold (Ht) defined as the maximum peak height of a surviving heterozygous allele, where its partner may have dropped out. The discrimination power of the system is estimated at 1 in 4.5 million, using a White Caucasian population database. Comparisons using artificially degraded samples profiled with both the SNP multiplex and AMPFISTR SGM plus (Applied Biosystems) demonstrated a greater likelihood of obtaining a profile using SNPs for certain sample types. Saliva stains degraded for 147 days generated an 81% complete SNP profile whilst short tandem repeats (STRs) were only 18% complete; similarly blood degraded for 243 days produced full SNP profiles but only 9% with STRs. Reproducibility studies showed concordance between SNP profiles for different sample types, such as blood, saliva, semen and hairs, for the same individual, both within and between different DNA extracts. 相似文献
997.
Murphy AM 《Forensic science international》2005,154(2-3):210-213
Prehistoric Polynesian skeletal remains are frequently being recovered in New Zealand due to the increasing pace of urbanisation. Since such material must often be reinterred quickly, it is important that the sex of individuals be determined from the remains in a relatively short time. For this purpose, discriminant function analysis was utilised for sex determination of prehistoric adult New Zealand Polynesian femora (47 male and 44 female). Three measurements of the femoral head were taken and subjected to Statistical Package for the Social Sciences (SPSS) discriminant function analysis. For the discriminant functions derived, accuracy of sex determination ranged from 80.9% to 82.4%. Reduction in error over random assignment by sex ranged from 62% to 65%. 相似文献
998.
The consumption of Delta9-tetrahydrocannabinol (THC) as cannabis has been shown to result in impaired and culpable driving. Testing drivers for the presence of THC in blood is problematic as THC and its metabolites may remain in the blood for several days following its consumption, even though the drug may no longer have an influence on driving performance. In the present study, the aim was to assess whether performance on the standardised field sobriety tests (SFSTs) provides a sensitive measure of impaired driving behaviour following the consumption of THC. In a repeated measures design, 40 participants consumed cigarettes that contained either 0% THC (placebo), 1.74% THC (low dose) or 2.93% THC (high dose). For each condition, after smoking a cigarette, participants performed the SFSTs on three occasions (5, 55 and 105 min after the smoking procedure had been completed) as well as a simulated driving test on two occasions (30 and 80 min after the smoking procedure had been completed). The results revealed that driving performance was not significantly impaired 30 min after the consumption of THC but was significantly impaired 80 min after the consumption of THC in both the low and high dose conditions. The percentage of participants whose driving performance was correctly classified as either impaired or not impaired based on the SFSTs ranged between 65.8 and 76.3%, across the two THC conditions. The results suggest that performance on the SFSTs provides a moderate predictor of driving impairment following the consumption of THC and as such, the SFSTs may provide an appropriate screening tool for authorities that wish to assess the driving capabilities of individuals suspected of being under the influence of a drug other than alcohol. 相似文献
999.
1000.
Although politicians, police, and others have often advocated the expansion of police employment in the effort to control crime, the empirical relationship between police employment and crime rates has seldom been systematically explored. This study incorporates variables which are causally related both to crime and police employment roles for the 252 northern and northeastern suburbs for which police employment and crime data are available for 1970–1972. Separate analyses of violent and property crime are undertaken, incorporating data on police employment as a causally related variable along with several other determinants of crime identified in earlier studies. The analysis suggests that police employment and crime rates are reciprocally related, and that these relationships offer more support for a “labeling” than a “deterrence” perspective. 相似文献