首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   6497篇
  免费   291篇
  国内免费   1篇
各国政治   373篇
工人农民   48篇
世界政治   940篇
外交国际关系   800篇
法律   3047篇
中国共产党   314篇
中国政治   597篇
政治理论   312篇
综合类   358篇
  2023年   28篇
  2022年   25篇
  2021年   16篇
  2020年   27篇
  2019年   42篇
  2018年   53篇
  2016年   35篇
  2015年   37篇
  2014年   165篇
  2013年   113篇
  2012年   396篇
  2011年   437篇
  2010年   231篇
  2009年   170篇
  2008年   330篇
  2007年   387篇
  2006年   418篇
  2005年   375篇
  2004年   348篇
  2003年   337篇
  2002年   301篇
  2001年   237篇
  2000年   234篇
  1999年   144篇
  1998年   108篇
  1997年   89篇
  1996年   77篇
  1995年   92篇
  1994年   101篇
  1993年   68篇
  1992年   55篇
  1991年   72篇
  1990年   61篇
  1989年   71篇
  1988年   109篇
  1987年   89篇
  1986年   83篇
  1985年   93篇
  1984年   90篇
  1983年   97篇
  1982年   67篇
  1981年   71篇
  1980年   90篇
  1979年   48篇
  1977年   19篇
  1964年   25篇
  1962年   21篇
  1961年   18篇
  1959年   20篇
  1957年   16篇
排序方式: 共有6789条查询结果,搜索用时 31 毫秒
991.
Zhu B  Shen C  Qian G  Shi R  Dang Y  Zhu J  Huang P  Xu Y  Zhao Q  Ma J  Liu Y 《Forensic science international》2006,158(2-3):229-233
Eleven Y-STRs loci including minimal haplotypes (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, and DYS385a,b) and two additional loci, namely DYS438 and DYS439 have been co-amplified in 100 healthy unrelated males of Chinese Yi minority ethnic group using the Y-PLEX 5 and Y-PLEX 6 kit, in order to investigate allele and haplotype frequencies of Yi population, evaluate their usefulness in forensic paternity testing and human identification, and enrich Chinese population genetic informational resources. Out of a total of 100 individuals 85 showed different haplotypes, while 8 haplotypes occurred more than once. The overall haplotype diversity for 11 Y-STRs loci was 0.9945.  相似文献   
992.
Lipid-deposits in internal organs, e.g. nephrons, are discussed as reliable marker to determine hypothermia as cause of death. While investigations concerning lipid vacuoles in the epithelium of the renal tubules are already published, there is no systematic information available about hypothermia and lipid deposits in cardiomyocytes. Therefore, this retrospective study presents the first results of lipid-stainings of myocardial samples taken by autopsies in hypothermia-cases in comparison to samples from a control group. It was the aim of the study to clarify the conceivable causal relationship between death due to hypothermia and lipid-deposits apart from lipofuscin and fatty degeneration, respectively, in cardiomyocytes.  相似文献   
993.
Historically, fatal injury monitoring and surveillance have relied on mortality data derived from death certificates (DC). However, problems associated with utilizing DC have been well documented. Recently, access to and utilization of hospital discharge data (HDD) have offered a new and important secondary source of data regarding in-hospital deaths. However, studies have shown that discrepancies between the HDD and the corresponding DC often exist. This discrepancy was especially evident when comparing HDD to the vital statistics data (VSD) for deaths by falls among those aged 65 and over in 19 states.This was a retrospective forensic review of elderly (age 65 and over) fall-associated fatalities (E880-E888) identified from HDD and VSD in Allegheny County, Pennsylvania, between 1997 and 1998. Seventy-seven cases were identified, with the original manner of death listed as natural (34), suicide (1), and accidental (42) on the DC. Following a forensic review of the cases, the manner of the death on the DC should have been changed from natural to accidental in 28% (n = 12) of the cases, representing an undercount in the VSD. Undercounts were due to a failure of clinicians to account for the significance of a fall event that contributed to subsequent pathology and death. In addition, in that 22% (n = 17) of the HDD fall-associated deaths, the fall did not contribute directly or sequentially to the underlying cause of death, thereby representing an overcount in the HDD.Based on these findings we recommend (1) elderly fall surveillance systems should only count HDD E-coded falls that demonstrate a serious traumatic injury which directly or subsequently results in death, (2) all in-hospital fall-associated deaths should be reported to and reviewed by coroner/Medical Examiner offices for determination of the cause and manner of death, and (3) physicians should be better educated in properly completing death certificates.  相似文献   
994.
To describe the epidemiology of suicide by hanging, in Transkei region of South Africa. This is a record review of the autopsy register from 1993 to 2003. There is an increasing trend of hangings from 5.2 per 100,000 to 16.2 in 2003. The highest was in the 20- to 29-year age group. The least number of hangings of 2.2 per 100,000 was in those over 70 years of age. Males (86.4%) outnumber females. The ratio of male to female suicide is 6.4:1. The 2 youngest suicide victims were also males aged 9 years. Peak of these hangings is in May and November and least in September. There is increasing trend of hanging especially among young adults between 20 and 29 years old.  相似文献   
995.
Homicide with subsequent hiding of the body using setting in concrete or sealing with bricks are rarely seen forensic cases. The article describes the circumstances and findings of six cases in which bodies were encased with concrete and/or bricks. In all cases, the offenders were male, in one case together with his wife and--except for one case--the victims were related to the offender. The causes of death were heterogeneous (suffocation, blunt force, shot) and the motive mainly domestic quarrel. Setting corpses in concrete and/or sealing with bricks does not prevent smell, slows decomposition and therefore complicates the estimation of the post mortem interval.  相似文献   
996.
Y-chromosomal STRs loci were analyzed from a sample of 119 healthy unrelated autochthonous male individuals of Chinese Tibetan ethnic minority group using a multiplex PCR system. Allele and haplotype frequencies for DYS19, DYS389 I, DYS389 II, DYS390, DYS391, DYS392, DYS393, DYS385a,b, DYS438, and DYS439 were determined by the Y-PLEXtrade mark 12 kit. The gene diversity values for the Y-STRs loci ranged from 0.3347 (DYS438) to 0.9547 (DYS385a,b). A total of 110 haplotypes were identified in the Y-STR loci, among which 104 were unique, while six occurred more than once. The overall haplotype diversity for the Y-STRs loci was 0.9981, and the discrimination capacity was 0.9897. The results in the present study can be used for routine forensic application in the region, and enrich Chinese ethnical genetic informational resources.  相似文献   
997.
Spinal epidural haematomas (sEDH) can be regarded as rare events, in principle a spontaneous and a traumatic aetiology can be distinguished. Spontaneous spinal epidural haematomas can arise, e.g. from vascular malformations, coagulopathies, etc. On the other hand, traumatic sEDH are related to, e.g. spinal trauma or intraoperative vascular injuries. With regard to clinical significance, spinal epidural haematomas accompanied by transient mild neurological symptoms up to lethal outcomes have been observed. We report on a 53-year-old male alcoholic who was found in the kitchen of his asylum in a grotesquely fixed body position, with his head and cervical spine in a maximum anteflected position. A general practitioner had ruled for a non-natural manner of death due to "broken neck" and alcohol intoxication, therefore, the prosecution authorities called for a medicolegal autopsy. At autopsy, paravertebral soft tissue haemorrhage in between the shoulder blades was disclosed. Furthermore, a spinal epidural haematoma, extending from the foramen magnum down to the middle portion of the thoracic spine was found. No fractures of vertebrae nor lesions of spine ligaments or bleedings of intervertebral discs were found. Blood alcohol concentration was determined 1.92 g/l and urine alcohol concentration was 1.76 g/l. Further morphological findings were cerebral oedema and cardiac hypertrophy; the urinary bladder was found filled to bursting. Neuropathological investigations confirmed the presence of the spinal epidural haematoma and assigned lethal significance to this finding. There were no histological signs of axonal injury. Reconstruction revealed that when sitting on a chair in a drunk condition, the individual's upper part of the body had fallen backwards in the corner and subsequently got stuck with maximum anteflection of the head and cervical spine, causing rupture of vessels and spinal epidural haematoma. Acute respiratory failure caused by impairment of the phrenic nerve following spinal epidural haematoma with potential synergism of alcohol intoxication was ascertained as the cause of death.  相似文献   
998.
The objective of this study was to develop a two-step strategy for analysis of opiates and cocaine in hair samples involving an immunological screening procedure followed by confirmation of results using gas chromatography-mass spectrometry (GC-MS). A semi-quantitative automated competitive enzyme-linked immunosorbent assay (ELISA) methodology using Oral Fluid Micro-Plate Enzyme Immunoassays (Orasure Technologies, Inc.) was developed and validated. Applicability was proven by analysis of authentic head hair samples from drug users (n=103) and from opiate associated fatalities (n=21). The optimum cutoff values for the ELISA tests were 0.1 ng cocaine-equivalents/mg hair and 0.05 ng morphine-equivalents/mg hair using a 50 mg hair sample. Both ELISA tests had a sensitivity of 100%, the specificity was 66% for cocaine-equivalents and 42% for morphine-equivalents. The intraassay precision was 11% for the cocaine and 3% for the opiates ELISA, while interassay precision was 12% for the cocaine and 4% for the opiates ELISA test. The actual analyte concentrations in the hair samples were determined using GC-MS and were between 0.04 and 5.20 ng/mg for heroin (HER), between 0.04 and 30.01 ng/mg for 6-monoacetylmorphine (MAM), between 0.03 and 11.87 ng/mg for morphine (MOR), between 0.02 and 1.84 ng/mg for codeine (COD), between 0.02 and 2.48 ng/mg for acetylcodeine (AC), between 0.01 and 21.37 ng/mg for cocaine (COC), between 0.03 and 10.51 ng/mg for benzoylecgonine (BE) and between 0.05 and 1.26 ng/mg for cocaethylene (CE). The automated ELISA tests were proven to be valid screening procedures for the detection of cocaine and opiates in hair as confirmed by GC-MS. Screening methods provide rapid and inexpensive automated pre-test procedures to detect drugs in hair or other matrices. For forensic purposes screening therefore represents an ideal complement to routinely applied GC-MS procedures.  相似文献   
999.
A method for the simultaneous determination of cocaine (COC) and cocaethylene (CE) in human hair was developed, using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS) as analytical technique to identify and quantify the drugs. Selected ion monitoring (SIM) mode was used to obtain higher sensitivity. The deuterated-labeled analogues were used as internal standards. The detector response was linear for the drugs studied over the range 0.4-15 ng/mg, with correlation coefficients higher than 0.995. The coefficients of variation oscillated between 0.65% and 14.18% and the accuracy was in the range from 0.73% to 11.20%. The limits of quantitation and detection were found to be acceptable. Finally, this method was applied to 15 hair samples from cocaine users, obtaining positive results in all cases. The mean concentrations were 5.39 ng/mg (range: 0.43-8.98 ng/mg) for cocaine and 1.11 ng/mg (range: 0.42-2.23 ng/mg) for cocaethylene.  相似文献   
1000.
The purpose of this study was to determine the performance characteristics of the Cozart Amphetamine Microplate EIA for detecting amphetamine in oral fluid. Oral fluid samples were collected using the Cozart RapiScan Collection System from 135 volunteer donors from drug treatment clinics. A further 35 oral fluid samples were collected from volunteer donors who were not drug users. The samples were analyzed in the laboratory using the Cozart Amphetamine Microplate EIA and confirmed using gas chromatography-mass spectrometry (GC-MS). The samples were stored frozen until analysis by GC-MS. The intra-assay precision for the Cozart Amphetamine Microplate EIA for amphetamine in oral fluid over forty assays was 2.74-7.1% CV (within assay) and 3.4-7.0% CV (within day). A total of 78 samples were positive for various amphetamines and related designer drugs. The Cozart Amphetamine Microplate EIA, using a cutoff of 45 ng/ml amphetamine equivalents in neat oral fluid, had a sensitivity of 91.7+/-3.3% and a specificity of 95.9+/-1.9% versus GC-MS using a cutoff of 30 ng/ml. A series of potential adulterants of oral fluid were evaluated and shown not to alter the outcome of the test result.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号