全文获取类型
收费全文 | 14888篇 |
免费 | 1319篇 |
专业分类
各国政治 | 724篇 |
工人农民 | 452篇 |
世界政治 | 1199篇 |
外交国际关系 | 529篇 |
法律 | 10127篇 |
中国共产党 | 2篇 |
中国政治 | 102篇 |
政治理论 | 2961篇 |
综合类 | 111篇 |
出版年
2021年 | 75篇 |
2020年 | 389篇 |
2019年 | 395篇 |
2018年 | 481篇 |
2017年 | 558篇 |
2016年 | 575篇 |
2015年 | 497篇 |
2014年 | 502篇 |
2013年 | 1744篇 |
2012年 | 347篇 |
2011年 | 450篇 |
2010年 | 606篇 |
2009年 | 588篇 |
2008年 | 425篇 |
2007年 | 380篇 |
2006年 | 455篇 |
2005年 | 344篇 |
2004年 | 328篇 |
2003年 | 307篇 |
2002年 | 291篇 |
2001年 | 508篇 |
2000年 | 407篇 |
1999年 | 363篇 |
1998年 | 202篇 |
1997年 | 183篇 |
1996年 | 147篇 |
1995年 | 186篇 |
1994年 | 188篇 |
1993年 | 158篇 |
1992年 | 244篇 |
1991年 | 281篇 |
1990年 | 242篇 |
1989年 | 269篇 |
1988年 | 241篇 |
1987年 | 213篇 |
1986年 | 251篇 |
1985年 | 239篇 |
1984年 | 243篇 |
1983年 | 213篇 |
1982年 | 177篇 |
1981年 | 150篇 |
1980年 | 155篇 |
1979年 | 166篇 |
1978年 | 114篇 |
1977年 | 94篇 |
1976年 | 84篇 |
1975年 | 78篇 |
1974年 | 95篇 |
1973年 | 71篇 |
1971年 | 61篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Gel ink pens have become a common writing instrument in the United States. Questioned document examiners often attempt to optically differentiate gel inks from each other and from other non-ballpoint ink writings (e.g., those from roller-ball pens). Since early formulations were primarily pigment-based, they do not elute when analyzed by thin-layer chromatography. However, recent gel ink formulations (i.e., within the past five years) include dye-based inks that can be easily separated. This study differentiates black gel inks using optical and chemical techniques. The techniques include: microscopy, visible and near infrared reflectance, near infrared luminescence, thin-layer chromatography (TLC), spot tests, and gas chromatography/mass spectrometry (GC/MS). As a result of this study a flow chart has been developed allowing for a systematic determination of a questioned ink. In addition, an analysis of volatile compounds found in gel inks revealed that there are some unique ingredients that may be found in gel inks that are not typically found in other non-ballpoint inks. 相似文献
992.
The pathomorphology of intoxication of alcohol surrogates is described. A high frequency rate of DIC-syndrome is shown for the condition. A majority of thrombi accumulates at places with the highest concentrations of toxic substances as well as at those places, through which poisoning substances are brought out of the body, i.e. in the liver (since toxic substances are introduced perorally) and kidneys. Thrombi were detected in all internals, including the brain, in lethal intoxication. The immediate toxic effect from methanol and from higher spirits can matter in the genesis of changes, including acute swelling and chromatolysis with subsequent cell death. Exclusively cerebral or coagulopathic-cerebral types of thanatogenesis were registered in studied case of intoxication. 相似文献
993.
Kornienko IV Vodolazhskiĭ DI Afanas'eva GV Ivanov PL 《Sudebno-meditsinskaia ekspertiza》2004,47(6):27-32
Polymorphism of mDNA D-loop central region (CR), positions 16366-0072) was studied versus hypervariable sections (HVS1), positions 16024-16365, and HVS2, positions 00073-00340, for a sample of 71 residents of the Russian Federation. Ten polymorphic positions with 56 nucleotide substitutions, 55 of which are transitions, were detect in the CR section; no insertions or deletions were found there. It was proven as possible to use the mDNA CR locus as an additional identification marker in the forensic-expert of the mDNA control region. The probability of random coincidence (RC) of haplotypes in joint typing of HVS1, HVS2 and CR made 0.0208, which is 1.4-fold less versus the same parameter for haplotypes HVS1/HVS2 (RC = 0.0284). 相似文献
994.
995.
Szentmariay IF Laszik A Sotonyi P 《The American journal of forensic medicine and pathology》2004,25(4):324-326
A 70-year-old male patient with a 23-year-old history of right lower lung lobectomy for primary pulmonary adenocarcinoma (T1 N0 M0) presented with recurrent bronchopneumonia and purulent sputum. Pleural callus, lung abscess, bronchopleural fistula, and stitch granulomas were confirmed by chest x-ray, computed tomography scan, and bronchoscopy in the background of his complaints. An attempt to remove the bronchial purulent discharge and tissue sampling was made by using a flexible bronchoscope. The area of the lower trachea suddenly became clogged during bronchoscopic removal of the suspected piece of tissue (which later turned out to be organizing surgical gauze). The resuscitation following ventricular fibrillation failed to save the patient's life. The forensic postmortem examination confirmed the position of the foreign body extending from the abscess cavity, crossing the midline at carina and obstructing the lower trachea. This foreign body was a remnant of the surgical gauze left behind during a thoracic surgery 23 years ago. 相似文献
996.
997.
Lora-Tamayo C Tena T Rodríguez A Moreno D Sancho JR Enseñat P Muela F 《Forensic science international》2004,140(2-3):195-206
A total of 137 urine samples and 46 serum samples, corresponding to 154 self-confessed designer drugs consumers in Ibiza island, were analyzed for the presence of designer drugs: amphetamine and amphetamine derivatives (methamphetamine, methylenedioxymethamphetamine (MDMA), methylenedioxyethylamphetamine (MDEA), methylenedioxyamphetamine (MDA), p-methoxymethylamphetamine (PMMA), p-methoxyamphetamine (PMA), etc.), ketamine and gamma-hydroxybutyric acid. Among this population, coming both from the forensic clinic and from the emergency room of a hospital, a total of 99 cases were found positive for some designer drug. This study shows the prevalence of methylenedioxymethamphetamine (MDMA) among designer drug users, sole or in association with other drugs. Also, the mixture of MDMA with other designer drugs, ethanol and/or cocaine is shown to be more likely to produce toxic symptoms requiring clinical attendance in a hospital emergency room. These findings along with the consumption history, the concentrations of drugs and metabolites in urine and serum and the toxicological significance for the interpretation of some MDMA metabolites such as 4-hydroxy-3-methoxymethamphetamine (HMMA) are discussed in this study. 相似文献
998.
Value of fetal autopsy after medical termination of pregnancy 总被引:2,自引:0,他引:2
Piercecchi-Marti MD Liprandi A Sigaudy S Fredouille C Adalian P Figarella-Branger D Pellissier JF 《Forensic science international》2004,144(1):7-10
We carried out a retrospective study of 352 medical terminations of pregnancy (MTP) carried out in a large French administrative region over two consecutive years. We analysed the indications for MTP and then compared the prenatal ultrasound diagnosis with fetal autopsy findings in order to demonstrate the value of pathological examination of the fetus in prenatal diagnosis and genetic counselling as well as the need to check by autopsy the quality of ultrasound screening. Preliminary analysis of the indication for these MTP showed that in 69.9% ultrasound screening had been carried out, revealing mainly brain abnormalities (22.2%) and heart defects generally associated with chromosomal abnormalities (32.1%). Prenatal findings were in agreement with autopsy results, showing no false-positive prenatal diagnoses. However, in 7.9% of cases in which brain abnormalities were detected, confirmation was not possible at autopsy because of tissue autolysis, showing the need for optimal conditions of expulsion. In 35.8% of cases, confirmation of the diagnosis by autopsy was not useful for management but still added to medical knowledge and demonstrated to the mother the reality of the defects. In 50.9%, the autopsy findings were decisive for genetic counselling. 相似文献
999.
Characterization and haplotype analysis of 10 novel Y-STR loci in Chinese Han population 总被引:3,自引:0,他引:3
Dai HL Wang XD Li YB Wu J Zhang J Zhang HJ Dong JG Hou YP 《Forensic science international》2004,145(1):47-55
In this study, we analyzed allelic sequences of 10 novel Y-specific STR loci, DYS454, DYS510, DYS513, DYS520, DYS542, DYS544, DYS552, DYS561, DYS587 and DYS593, surveyed the distribution of haplotypes in a Chinese Han population. Extracted DNA was amplified with PCR, followed by a horizontal non-denaturing polyacrylamide gel electrophoresis with discontinuous buffer system. Purified alleles were sequenced on DNA sequencer (ABI Model 377) to verify the number of motif repeats. The number of alleles observed at each locus ranged from 3 to 8, yielding 102 haplotypes in 103 unrelated males samples. The allele diversity values for each locus ranged from 0.2099 (DYS544) to 0.7523 (DYS552). The haplotype diversity using all these loci was 0.9998. Our study revealed that they were valuable Y-specific markers for forensic applications. 相似文献
1000.
Bhana BD Kirk GM Dada MA 《The American journal of forensic medicine and pathology》2003,24(3):273-276
Firearm-related injuries are a leading cause of morbidity and mortality in South Africa. This retrospective autopsy study included all firearm-related fatalities seen at a central mortuary in Durban. These cases had initially been assessed by a clinician before death, from July 1998 to June 1999.A total of 322 cases of fatal gunshot wounds were reviewed. Medical records and postmortem findings were compared by data capture onto a spreadsheet. Twenty-eight cases were excluded because of surgical alteration of the wounds, making autopsy evaluation impossible. In 50.7% of cases, the number of wounds was correctly identified and in 55.1% the position was correctly identified. In only 36.1% of cases were the entry and exit wounds correctly identified. The total number of missed wounds was 504 (48.3% of cases). The majority of missed wounds were on the upper limbs (25%), with the anterior trunk (21.8%) and lower limbs (18.5%) making up the remainder. This study demonstrates that physicians in South Africa do not adequately document and interpret gunshot wounds, which may influence the treatment of the patient and have medicolegal consequences. Emphasis should be placed on undergraduate and postgraduate teaching for physicians to correctly identify, interpret, and document firearm wounds. 相似文献