全文获取类型
收费全文 | 16644篇 |
免费 | 483篇 |
专业分类
各国政治 | 701篇 |
工人农民 | 755篇 |
世界政治 | 1016篇 |
外交国际关系 | 568篇 |
法律 | 10441篇 |
中国共产党 | 34篇 |
中国政治 | 165篇 |
政治理论 | 3269篇 |
综合类 | 178篇 |
出版年
2020年 | 208篇 |
2019年 | 208篇 |
2018年 | 317篇 |
2017年 | 374篇 |
2016年 | 412篇 |
2015年 | 325篇 |
2014年 | 345篇 |
2013年 | 1577篇 |
2012年 | 376篇 |
2011年 | 415篇 |
2010年 | 351篇 |
2009年 | 407篇 |
2008年 | 487篇 |
2007年 | 515篇 |
2006年 | 501篇 |
2005年 | 432篇 |
2004年 | 418篇 |
2003年 | 388篇 |
2002年 | 355篇 |
2001年 | 581篇 |
2000年 | 530篇 |
1999年 | 458篇 |
1998年 | 243篇 |
1997年 | 186篇 |
1996年 | 206篇 |
1995年 | 173篇 |
1994年 | 198篇 |
1993年 | 185篇 |
1992年 | 306篇 |
1991年 | 378篇 |
1990年 | 351篇 |
1989年 | 323篇 |
1988年 | 347篇 |
1987年 | 354篇 |
1986年 | 360篇 |
1985年 | 325篇 |
1984年 | 286篇 |
1983年 | 271篇 |
1982年 | 173篇 |
1981年 | 203篇 |
1980年 | 166篇 |
1979年 | 222篇 |
1978年 | 168篇 |
1977年 | 137篇 |
1976年 | 116篇 |
1975年 | 142篇 |
1974年 | 148篇 |
1973年 | 152篇 |
1972年 | 100篇 |
1971年 | 104篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Postmortem redistribution of morphine and its metabolites 总被引:2,自引:0,他引:2
The postmortem redistribution of morphine, morphine-3-glucuronide, morphine-6-glucuronide and total morphine was assessed in 40 heroin-related deaths. In blood taken from subclavian, heart, and femoral regions, concentrations of morphine and its metabolites were similar. While there was a trend for higher concentrations in heart blood, when compared with femoral or subclavian blood, this was not significant. There was also no significant difference in concentrations between admission and autopsy blood in which the postmortem interval was on average 59 h. From our observations, significant postmortem redistribution of morphine and its metabolites seems unlikely. 相似文献
942.
Tahir MA Balraj E Luke L Gilbert T Hamby JE Amjad M 《Journal of forensic sciences》2000,45(4):902-907
A body was exhumed from the ground after 27 years. Samples of femur bone, tooth, and a fingernail were collected and successfully subjected to DNA extraction, quantitation, amplification, and subsequently typed for DQA1, polymarker, and nine STR loci. All three types of samples were typed for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S17, D7S820, and amelogenin using ABI Prism 377 DNA sequencer. 相似文献
943.
Mauricio-da-Silva L Silva RS Dellalibera E Donadi EA 《Journal of forensic sciences》2000,45(3):684-686
One hundred thirty-four unrelated Northeast Brazilian individuals were typed for the HPRTB, F13B, and LPL short tandem repeats (STRs). DNA was amplified by specific primers and identified by silver staining of polyacrylamide gels. The allelic frequencies of these loci were in agreement with Hardy-Weinberg proportions. The most frequent alleles were HPRTB*13, F13B*10, LPL*10. The combined probability of paternity and the discrimination power of these 3 STRs were high, permitting their utilization for forensic science purposes. 相似文献
944.
945.
Decomposition studies were conducted to determine differences in rates and patterns of decomposition of carcasses hanging and exposed on the surface of the soil. These studies were conducted between 17 October and 17 December 1997 inside of Diamond Head Crater on the island of Oahu, Hawaii. The animal model was the domestic pig. Sus scrofa. The rate of biomass removal from the hanging carcass was significantly slower than that observed for the control carcass during the bloat and decay stages of decomposition. Internal temperatures for the control carcass were elevated above the ambient air temperatures during the earlier stages of decomposition (bloated and decay), while those recorded for the hanging carcass approximated the ambient air temperatures. There was a greater diversity of arthropod species recorded and numbers of individuals observed were higher for the control carcass. A significant site of arthropod activity was observed on the surface of the soil immediately under the hanging carcass and this became the primary site of arthropod activity as decomposition progressed. 相似文献
946.
A technique that exposes fingerprint residue to a gaseous electrical discharge in nitrogen followed by treatment with ammonium hydrogen carbonate vapors to produce fluorescence is investigated. Particular attention is made to fluorescence observed via laser illumination at 514 nm. Insight into the nature of the fluorescent components is achieved through the use of thin-layer chromatography (TLC) of fingerprint residue. Results reported indicate the fluorescence observed is from previously non-fluorescent fractions of the fingerprint residue, and TLC results point towards lipid derivatives as a possible source of the fluorescence. 相似文献
947.
During STR analysis on the 310 Genetic Analyzer, retarded migration of GS500ROX size standards and alleles in some samples was observed. The contribution of reagents, capillary and performance optimized polymer POP 4 to the observed anomaly was experimentally eliminated. Variation in electrophoresis temperature between 55 degrees C and 65 degrees C did not alter the rate of migration of GX500ROX size standard and sample alleles. An eroded connector for the cathode mounted on the heat plate assembly caused the abnormal migration. Hence, it is important to verify the mobility of all fragments in the size standard for each sample to avoid any erroneous allele calls by the automated data analysis software. 相似文献
948.
Loss of heterozygosity detected in a short tandem repeat (STR) locus commonly used for human DNA identification 总被引:3,自引:0,他引:3
Rubocki RJ Duffy KJ Shepard KL McCue BJ Shepherd SJ Wisecarver JL 《Journal of forensic sciences》2000,45(5):1087-1089
Short tandem repeat (STR) markers are commonly used in basic genetic research and in human identification testing. Clinically, STRs can be used to study genetic alterations in tumors. A genetic deletion common to many types of cancer is referred to as the loss of heterozygosity (LOH). Numerous examples of LOH in cancer have been described and some have been mapped to areas located in close proximity to markers employed in human identity testing. Despite this fact, LOH has rarely been observed for STR loci commonly employed in forensic testing. Recently, for medico-legal purposes, we were asked to determine whether a tissue biopsy originated from a particular individual. For a reference source we assessed two specimens, one from normal tissue and one from cancerous tissue. When both reference specimens were used to generate DNA profiles, we observed LOH at one STR locus, D13S317. As demonstrated in other cancers only the cancerous biopsy demonstrated LOH. The forensic community should be cognizant of these unusual circumstances because, as identification of human DNA continues to be used more extensively, certain instances will arise in which reference material will not be readily available. In these situations, archived specimens may be employed as a reference source. Clinical specimens such as tissue biopsies should be used with caution if they have not been confirmed to contain normal tissue. 相似文献
949.
950.