全文获取类型
收费全文 | 19993篇 |
免费 | 1247篇 |
专业分类
各国政治 | 781篇 |
工人农民 | 908篇 |
世界政治 | 1259篇 |
外交国际关系 | 615篇 |
法律 | 14187篇 |
中国共产党 | 2篇 |
中国政治 | 120篇 |
政治理论 | 3243篇 |
综合类 | 125篇 |
出版年
2021年 | 100篇 |
2020年 | 452篇 |
2019年 | 470篇 |
2018年 | 601篇 |
2017年 | 609篇 |
2016年 | 704篇 |
2015年 | 525篇 |
2014年 | 566篇 |
2013年 | 1995篇 |
2012年 | 540篇 |
2011年 | 603篇 |
2010年 | 584篇 |
2009年 | 593篇 |
2008年 | 589篇 |
2007年 | 586篇 |
2006年 | 594篇 |
2005年 | 500篇 |
2004年 | 517篇 |
2003年 | 450篇 |
2002年 | 486篇 |
2001年 | 773篇 |
2000年 | 696篇 |
1999年 | 558篇 |
1998年 | 253篇 |
1997年 | 186篇 |
1996年 | 201篇 |
1995年 | 204篇 |
1994年 | 183篇 |
1993年 | 200篇 |
1992年 | 353篇 |
1991年 | 382篇 |
1990年 | 369篇 |
1989年 | 355篇 |
1988年 | 382篇 |
1987年 | 336篇 |
1986年 | 378篇 |
1985年 | 383篇 |
1984年 | 302篇 |
1983年 | 279篇 |
1982年 | 196篇 |
1981年 | 172篇 |
1980年 | 156篇 |
1979年 | 241篇 |
1978年 | 140篇 |
1977年 | 111篇 |
1976年 | 97篇 |
1975年 | 116篇 |
1974年 | 154篇 |
1973年 | 107篇 |
1972年 | 107篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
981.
Between 1976 and the middle of 2001, approximately 718 human executions occurred in the U.S. (a small segment of worldwide executions). Data regarding the medical aspects of these executions are not readily available. We searched all public domain data in the U.S. to obtain specific data for all persons executed in the U.S. since 1976. Of the five methods of execution used (lethal injection, lethal gas, electrocution, hanging, and firing squad), significant differences emerged as measured by rate of complications, duration of time spent by the condemned in the "death chamber," as well as duration of time from the onset of execution procedures to pronouncement of death. These data suggest that human executions are difficult to carry out. Human executions are associated with significant physical complications. These data may help inform future discussions on human executions. 相似文献
982.
A simple technique is presented for the longitudinal sectioning of hair samples without the need for any embedding medium. The technique applies to single hair samples that are placed in a groove of a particular depth and can either be scraped or cut to the desired level. Planar sections are obtained that reveal the internal structure of the sample and are ideal for the application of surface analytical techniques for the study of internal transverse and longitudinal distributions of xenobiotics. 相似文献
983.
984.
985.
Crystallographic analysis of the cerebrospinal fluid (CSF) was carried out in 18 cases of death from coronary disease and 19 cases of death from ethanol poisoning. The crystallograms were evaluated visually and by the stereoscopic picture. Specific features of the CSF crystal colonies growth in subjects dead from the above conditions are determined. 相似文献
986.
987.
988.
Torres MC Osuna E Pérez-Cárceles MD Gómez-Zapata M Luna A 《The American journal of forensic medicine and pathology》2002,23(2):155-158
The authors evaluated the usefulness of the postmortem biochemical analysis of ionic ratios in different parts of the heart and their relation to cardiac damage caused by chest trauma, as observed by anatomopathologic study. Fifty-nine 59 cases were studied, selected from routine necropsies, and samples were taken from different sites of cardiac tissue. The cause of death was trauma in 40 cases and nontraumatic causes in 19 cases. The object of this study was to analyze the levels of Na+, K+, Ca+2, Mg+2, and Zn+2 in different zones of the heart, and the relationship between intracellular and extracellular ion ratios and the different causes of death and any anatomopathologic alterations observed. The biochemical tests revealed a possible relation between the ionic values and cause of death. Alterations in cell membrane permeability and corresponding modification of the ionic ratios were produced earlier than histologic alterations, which need longer to establish themselves whether or not they follow a traumatic process. 相似文献
989.
Soares-Vieira JA Billerbeck AE Pinto EM Iwamura ES Bilharinho de Mendonça B Otto PA 《The American journal of forensic medicine and pathology》2002,23(2):186-190
Gene and genotype frequencies in relation to the D3S1358, vWA, FGA, TH01, TPOX, CSF1PO, D5S818, D13S317, and D7S820 loci were determined in a sample of 290 unrelated individuals (204 Caucasians and 86 mulattoes) living in the city of S?o Paulo, Brazil. The sex test Amelogenin was also performed in all subjects from our sample, revealing the expected sex in all instances. Allele frequency data obtained from the analysis of these samples were in the usual range of other population groups with similar racial background. In the sample of Caucasian individuals, panmictic proportions were ruled out in relation to TPOX and CSF1PO loci, but only in the latter was the overall frequency of heterozygotes significantly less than expected. In the sample of mulattoes, Hardy-Weinberg proportions were rejected in relation to FGA and CSF1PO loci, but in no instance were the overall numbers of heterozygotes different from the corresponding expected ones under panmixia. Taking into account all this and also the number of tests performed, the degree of genetic heterogeneity of Brazilian populations, and the critical level reached by the significant results (1% < alpha<5%), the departures from panmixia here observed can be considered to be negligible in altering significantly biologic relationship odds calculated under the assumption of random matings. 相似文献
990.
Trivedi R Chattopadhyay P Kashyap VK 《The American journal of forensic medicine and pathology》2002,23(2):191-196
A new method for better recovery of DNA suitable for amplification of hypervariable loci from fragments of teeth, consisting of two steps-scraping and aspiration, and extensive decalcification-is reported. Higher yields of high molecular weight DNA were obtained from the root, pulp, and crown of all kinds of 120 teeth, irrespective of gender, age, and source of teeth. HLA DQA1, 5 poly markers (LDLR, GYPA, HBGG, D7S8, and Gc), and other 12 short tandem repeat loci (HPRTB, F13B, LPL, D13S317, D7S820, D5S818, D21S11, D18S51, FGA, D8S1179, D3S1358, and vWA) could be successfully amplified and typed from recovered DNA. 相似文献