全文获取类型
收费全文 | 31280篇 |
免费 | 987篇 |
国内免费 | 5篇 |
专业分类
各国政治 | 1341篇 |
工人农民 | 1278篇 |
世界政治 | 2431篇 |
外交国际关系 | 1114篇 |
法律 | 19133篇 |
中国共产党 | 8篇 |
中国政治 | 216篇 |
政治理论 | 6425篇 |
综合类 | 326篇 |
出版年
2020年 | 422篇 |
2019年 | 495篇 |
2018年 | 632篇 |
2017年 | 759篇 |
2016年 | 777篇 |
2015年 | 551篇 |
2014年 | 612篇 |
2013年 | 3052篇 |
2012年 | 804篇 |
2011年 | 831篇 |
2010年 | 679篇 |
2009年 | 738篇 |
2008年 | 862篇 |
2007年 | 931篇 |
2006年 | 898篇 |
2005年 | 797篇 |
2004年 | 811篇 |
2003年 | 861篇 |
2002年 | 755篇 |
2001年 | 1194篇 |
2000年 | 1058篇 |
1999年 | 888篇 |
1998年 | 505篇 |
1997年 | 390篇 |
1996年 | 380篇 |
1995年 | 348篇 |
1994年 | 425篇 |
1993年 | 392篇 |
1992年 | 589篇 |
1991年 | 652篇 |
1990年 | 600篇 |
1989年 | 572篇 |
1988年 | 592篇 |
1987年 | 560篇 |
1986年 | 597篇 |
1985年 | 558篇 |
1984年 | 472篇 |
1983年 | 503篇 |
1982年 | 402篇 |
1981年 | 390篇 |
1980年 | 286篇 |
1979年 | 396篇 |
1978年 | 277篇 |
1977年 | 236篇 |
1976年 | 205篇 |
1975年 | 229篇 |
1974年 | 256篇 |
1973年 | 212篇 |
1972年 | 202篇 |
1971年 | 182篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
101.
We investigated the differences in the levels of carboxyhemoglobin (COHb), cyanide (HCN) and petroleum fuels (gasoline and kerosene) between left and right ventricular bloods from fire victims. COHb was slightly, and HCN and petroleum fuels were markedly higher levels in the left than those in the right. These effects were so called 'first pass phenomena' due to the circulation, diffusion and metabolization before the deaths of fire victims. 相似文献
102.
The results of additional validation studies of a sensitive microplate hemagglutination assay for ABO reverse grouping of bloodstains are presented. The results of the validation study demonstrate the reliability of the microplate assay for use in routine serological casework. Based on these studies, the microplate assay has now replaced the Lattes crust test for ABO reverse grouping of bloodstains in the FBI Laboratory. 相似文献
103.
Negotiation Journal - 相似文献
104.
Paul A. Papayoanou 《国际研究季刊》1997,41(1):113-140
To account for variance in great powers responses to threats and the implications for the peacefulness of the international system since the late nineteenth century, this article elucidates a theory which refines and synthesizes economic liberal perspectives and realist balance of power theory. I argue that different patterns and levels of economic interdependence in the great power system generate societal-based economic constraints on, or incentives for, state leaders of status quo powers hoping to mobilize economic resources and political support to oppose perceived threats. This mobilization process influences strongly the preferences of status quo powers, other states beliefs about those preferences, and the interpretation of signals in balance of power politics. In this way, economic ties influence the strategies great powers pursue. Firm balancing policies conducive to peace in the international system are most likely, I then hypothesize, when there are extensive economic ties among status quo powers and few or no such links between them and perceived threatening powers. When economic interdependence is not significant between status quo powers or if status quo powers have strong economic links with threatening powers, weaker balancing postures and conciliatory policies by status quo powers, and aggression by aspiring revisionist powers, are more likely. I then illustrate how these hypotheses explain the development of the Franco-Russian alliance of the 1890s and its effectiveness as a deterrent of Germany up to 1905, British ambivalence toward Germany from 1906 to the First World War, the weakness of British, French, Soviet, and American behavior toward Germany in the 1930s and World War II, and the American and European responses to the Soviet threat, including the NATO alliance, and the "long peace" of the post-1945 era. 相似文献
105.
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
106.
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
107.
One case of the erroneous administration of deslanoside and high level of drug in antemortem plasma and postmortem specimens has been reported owing to the unusual surrounding circumstances. Deslanoside in antemortem plasma was determined by FPIA and the analysis was done by HPLC in the postmortem tissue samples. The analytical results and methods used in the examinations are discussed in the following paper. 相似文献
108.
109.
110.