全文获取类型
收费全文 | 16501篇 |
免费 | 804篇 |
专业分类
各国政治 | 838篇 |
工人农民 | 587篇 |
世界政治 | 1443篇 |
外交国际关系 | 780篇 |
法律 | 9670篇 |
中国共产党 | 1篇 |
中国政治 | 109篇 |
政治理论 | 3773篇 |
综合类 | 104篇 |
出版年
2023年 | 74篇 |
2021年 | 106篇 |
2020年 | 283篇 |
2019年 | 358篇 |
2018年 | 455篇 |
2017年 | 518篇 |
2016年 | 571篇 |
2015年 | 399篇 |
2014年 | 441篇 |
2013年 | 1968篇 |
2012年 | 435篇 |
2011年 | 495篇 |
2010年 | 451篇 |
2009年 | 470篇 |
2008年 | 509篇 |
2007年 | 525篇 |
2006年 | 520篇 |
2005年 | 453篇 |
2004年 | 453篇 |
2003年 | 425篇 |
2002年 | 415篇 |
2001年 | 580篇 |
2000年 | 533篇 |
1999年 | 406篇 |
1998年 | 270篇 |
1997年 | 243篇 |
1996年 | 201篇 |
1995年 | 182篇 |
1994年 | 221篇 |
1993年 | 212篇 |
1992年 | 267篇 |
1991年 | 290篇 |
1990年 | 274篇 |
1989年 | 273篇 |
1988年 | 270篇 |
1987年 | 233篇 |
1986年 | 286篇 |
1985年 | 258篇 |
1984年 | 199篇 |
1983年 | 203篇 |
1982年 | 146篇 |
1981年 | 154篇 |
1980年 | 111篇 |
1979年 | 153篇 |
1978年 | 95篇 |
1977年 | 90篇 |
1976年 | 84篇 |
1974年 | 104篇 |
1973年 | 78篇 |
1972年 | 72篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
71.
72.
The polymerase chain reaction (PCR) method of specific gene amplification was used in casework to synthesize millions of copies of the polymorphic second exon of the human leukocyte antigen (HLA)-DQ alpha (or DQA1) locus from a variety of evidence samples. The HLA-DQ alpha allelic variants in the amplified deoxyribonucleic acid (DNA) were determined in a rapid non-radioactive test by hybridization to sequence-specific oligonucleotide probes in both the dot-blot and reverse dot-blot formats. This genetic typing system has been subjected to blind proficiency testing; the performance of this test in the analysis of experimentally mixed samples was also evaluated. As of August 1990, over 250 cases have been tested and more than 2000 individual evidence (bloodstains, semen stains, individual hairs, bone fragments, and tissue sections) and reference samples have been analyzed. The first 198 of these cases are summarized in this paper; in 65% of the cases with conclusive results a suspect was included, and in 35%, all suspects were excluded. Individual cases as well as some of the general issues relating to forensic science analysis and this genetic typing system are discussed. The high rate of exclusion reported here combined with the ability of PCR to type old evidence samples suggests the relevance of this genetic test for postconviction review; two cases in which the convicted suspect was excluded are discussed. 相似文献
73.
Postmortem changes in sulfide concentrations in body tissues were examined in autopsied rats exposed to hydrogen sulfide concentrations of 550 to 650 ppm, and in nonexposed rats and humans. Analyses were made by gas chromatography, following an extractive alkylation. Sulfide concentrations in the blood, liver, and kidneys of rats increased in both the exposed and nonexposed groups, depending on the lapse of time after death. On the other hand, the lung, brain, and muscle showed little or no change in sulfide concentration with elapse of time after death. The data obtained from human tissues were almost the same as those for rats, except data for blood, in which no or little increase of sulfide was observed. 相似文献
74.
C J Kim B H Kwak S D Kim S P Kim 《The American journal of forensic medicine and pathology》1992,13(3):211-213
A 22-year-old Korean soldier, who had received blows to the neck and epigastrium from an officer 10 h earlier, suddenly died after massive hematemesis. He had been in relatively good health except for episodes of blood-tinged vomiting approximately 5 and 7 months prior to this event. Postmortem examination revealed angiodysplasia involving the gastroesophageal junction, and the stomach was distended with blood. No abnormal findings were present around the whole viscera, and the duodenum was free of blood. The pathologic significance of upper gastrointestinal angiodysplasia as a potential source of bleeding and a chronologic correlation between the trauma and bleeding are discussed. 相似文献
75.
While the beneficial aspects of a public accounting office's activity are not disputed here, it is argued in this article that four major distortions are produced: the concern with administrative rationality overlooks costs elsewhere (Section 2); budgetary aspects are overvalued compared to other issues (Section 3); incentives-oriented behavior is suppressed (Section 4); and the evaluation is biased by concentrating on minor, instead of major, aspects of inefficiency (Section 5). Section 6 considers alternatives to public accounting offices and makes some suggestions for new institutional arrangements particularly for constitutional rules. 相似文献
76.
The primary aim of this paper is to review the literature on preadolescent friendships in order to examine the relationship between preadolescent friendships and social support in adulthood. Social supports are important to health, both directly and as a stress buffer. Few studies, however, have specifically examined adult social supports from the perspective of their developmental precursors and critical developmental periods. Some data indicate that the preadolescent period may be of particular importance to the development of adult social skills and ties. Observational and empirical studies of preadolescent peer relationships, and in particular best friendships, suggest unique and critical contributions to adult social relatedness. Present research is suggestive but is insufficient to validate preadolescence as a critical period in adult social relatedness. Our review has implications for better understanding the mechanisms by which preadolescent friendships effect adult social support—an important mediator of the effects of stress on health. Further longitudinal study is needed.Received Ph.D. from University of Maryland. Research interests are social supports and psychological responses to trauma and disaster.Received M.D. from Yale University. Research interests are social supports and traumatic stress. 相似文献
77.
78.
Presented in this paper are the initial results involving the use of the nose or outer ear as temperature measurement sites to determine the postmortem period of the human corpse. Simple mathematical models for both sites are developed based on cooling curves of five corpses. Analysis of errors between actual and calculated postmortem intervals suggest that in its present form, the described methods would not be suitable for use in accurately determining the time since death of human corpses. 相似文献
79.
80.
This study examines a crucial question: What kind of effect do interdiction and other drug enforcement activities have on drug smuggling? Do they actually deter smuggling, or is their effect more one of disruption and displacement?... 相似文献