全文获取类型
收费全文 | 20460篇 |
免费 | 569篇 |
专业分类
各国政治 | 682篇 |
工人农民 | 991篇 |
世界政治 | 1343篇 |
外交国际关系 | 709篇 |
法律 | 13022篇 |
中国共产党 | 34篇 |
中国政治 | 201篇 |
政治理论 | 3870篇 |
综合类 | 177篇 |
出版年
2021年 | 125篇 |
2020年 | 257篇 |
2019年 | 292篇 |
2018年 | 495篇 |
2017年 | 451篇 |
2016年 | 570篇 |
2015年 | 371篇 |
2014年 | 422篇 |
2013年 | 1787篇 |
2012年 | 578篇 |
2011年 | 608篇 |
2010年 | 406篇 |
2009年 | 528篇 |
2008年 | 587篇 |
2007年 | 586篇 |
2006年 | 566篇 |
2005年 | 835篇 |
2004年 | 606篇 |
2003年 | 458篇 |
2002年 | 415篇 |
2001年 | 786篇 |
2000年 | 712篇 |
1999年 | 550篇 |
1998年 | 281篇 |
1997年 | 241篇 |
1996年 | 235篇 |
1995年 | 213篇 |
1994年 | 224篇 |
1993年 | 205篇 |
1992年 | 397篇 |
1991年 | 451篇 |
1990年 | 439篇 |
1989年 | 413篇 |
1988年 | 437篇 |
1987年 | 413篇 |
1986年 | 400篇 |
1985年 | 381篇 |
1984年 | 325篇 |
1983年 | 304篇 |
1982年 | 204篇 |
1981年 | 229篇 |
1980年 | 174篇 |
1979年 | 219篇 |
1978年 | 168篇 |
1977年 | 125篇 |
1976年 | 116篇 |
1975年 | 140篇 |
1974年 | 164篇 |
1973年 | 157篇 |
1971年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
D.S.T Lo T.C Chao S.E Ng-Ong Y.J Yao T.H Koh 《Forensic Science International Supplement Series》1997,90(3):626
Blood previously acidified with aqueous saturated ammonium chloride solution was extracted with ethyl acetate. The dried extract was subjected to acetonitrile–hexane partition. The acetonitrile portion was analysed for the presence of acidic and neutral drugs by HPLC–DAD (200 mm×2.1 mm I.D. microbore ODS-Hypersil column) and GC–FID (25 m narrow-bore×0.25 mm I.D. HP-5 column with 0.33 μm film thickness). The protocol was found to be suitable for both clinical toxicology (including emergency toxicology) and postmortem toxicology. At least 66 drugs of interest were unequivocally identified by RRTs (HPLC) and UV spectra (DAD) match while another 12 were unequivocally identified by double RRTs match (HPLC and GC). Quantitation was facilitated by incorporating calibration blood standards in each assay batch. The five drugs most commonly encountered in clinical blood specimens (1150 cases) were: paracetamol (47.4% of the cases); chlormezanone (6.6%), theophylline (1.74%), naproxen (1.65%) and mefenamic acid (1.56%). The following drugs were detected in toxicologically significant quantities in postmortem blood specimens (245 cases): phenobarbitone (1.22% of the cases), naproxen (0.82%), chlormezanone (0.82%), theophylline (0.82%), carbamazepine (0.41%) and paracetamol (0.41%). 相似文献
72.
73.
Attributions of blame for the first and latest episodes of violence were assessed in a sample of 139 couples who were referred to a mandatory domestic violence treatment program in the military. Use of a methodology which allows for reports of nonmutually exclusive categories of attribution from both members of the dyad revealed more complex patterns of attributions than reflected in the existing literature. In addition, there were low rates of agreement within couples as to who was to blame for the violence. Although both men and women exhibited a high frequency of blaming their partner for both episodes of violence, men were significantly more likely to blame themselves for the latest than for the first episode. Attributions of blame were related to contextual variables in both men and women. Sex specific relationships emerged. These results were discussed with specific reference to predictions derived from attribution theory and their clinical implications. 相似文献
74.
75.
Good gas chromatography (GC) separation of molecules is essential for clean gas chromatography/mass spectrometry (GC/MS) confirmation of compounds. The trifluoro derivatives of ephedrine (E) and methamphetamine (MA) coelute on dimethyl silicone capillary columns, such as DB-1, which are most commonly used by chromatographers. Methods are described to separate E and MA to aid GC/MS confirmations of methamphetamine, ephedrine, or both E and MA together, whichever may be present in Enzyme Immunoassay (EIA)-analyzed amphetamine-positive urine samples. The use of the heptafluoro derivatives of E and MA on a DB-1 column, or the trifluoro derivatives of E and MA on a DB-17 column, is suggested for good gas chromatographic separation. 相似文献
76.
This article outlines the new regionalism movement and its metropolitanagenda, reviews federal efforts to promote new regionalism underISTEA and TEA21, considers how the new federal policieschanged the role of metropolitan planning organizations (MPOs)in transportation planning by examining the MPO for the Louisvillemetropolis, and assesses the MPO process in Louisville. Thelocal decision of whether to build a new bridge across the OhioRiver was a major test of the enhanced MPO process. Federaltransportation policies enhanced regional coordination and cooperationin transportation planning in the Louisville metropolis resultingin a consensus plan to build two bridges across the Ohio River.However, the MPO process did not lead to the development ofa metropolitan-wide interest or perspective. Moreover, the newregionalist agenda was not advanced because sprawl was not afactor in the decision on whether and where to build the bridges. 相似文献
77.
78.
79.
The enzyme activity of phosphoglucomutase (PGM) has been investigated in red cell haemolysates from 142 individuals and compared to the sub-type as determined by isoelectric focusing. The 10 phenotypes showed significant differences in PGM-activity which indicates that there is a correlation between the level of activity and the isolelectric point of homozygotes. No indication of silent alleles or alleles with reduced activity was found in this collective. 相似文献
80.