全文获取类型
收费全文 | 11089篇 |
免费 | 307篇 |
专业分类
各国政治 | 437篇 |
工人农民 | 383篇 |
世界政治 | 755篇 |
外交国际关系 | 382篇 |
法律 | 6910篇 |
中国政治 | 71篇 |
政治理论 | 2366篇 |
综合类 | 92篇 |
出版年
2020年 | 108篇 |
2019年 | 158篇 |
2018年 | 198篇 |
2017年 | 222篇 |
2016年 | 227篇 |
2015年 | 170篇 |
2014年 | 193篇 |
2013年 | 1032篇 |
2012年 | 225篇 |
2011年 | 280篇 |
2010年 | 224篇 |
2009年 | 284篇 |
2008年 | 296篇 |
2007年 | 290篇 |
2006年 | 279篇 |
2005年 | 257篇 |
2004年 | 260篇 |
2003年 | 258篇 |
2002年 | 245篇 |
2001年 | 432篇 |
2000年 | 373篇 |
1999年 | 301篇 |
1998年 | 174篇 |
1997年 | 131篇 |
1996年 | 143篇 |
1995年 | 145篇 |
1994年 | 144篇 |
1993年 | 143篇 |
1992年 | 237篇 |
1991年 | 258篇 |
1990年 | 246篇 |
1989年 | 255篇 |
1988年 | 231篇 |
1987年 | 230篇 |
1986年 | 266篇 |
1985年 | 262篇 |
1984年 | 231篇 |
1983年 | 220篇 |
1982年 | 154篇 |
1981年 | 130篇 |
1980年 | 120篇 |
1979年 | 154篇 |
1978年 | 91篇 |
1977年 | 118篇 |
1976年 | 98篇 |
1975年 | 73篇 |
1974年 | 91篇 |
1973年 | 88篇 |
1972年 | 84篇 |
1971年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
71.
A number of recent studies have explored the consequences ofinterracial peer effects on the academic and social performanceof minority students. This article contributes to that discussion,focusing, however, on perceptions rather than behaviors. Theanalysis suggests that exposure to white peers is associatedwith declining perceptions of racial justice among black andLatino high school students. While cautioning against causalinterpretations of this finding, the article suggests that theintegrationist aims of Brown v. Board of Education will notbe satisfied without more thoughtful and vigorous desegregationefforts. 相似文献
72.
73.
74.
Deoxyribonucleic acid (DNA) typing of ribosomal ribonucleic acid (rRNA) genes was performed with a polymerase chain reaction (PCR) assay for species identification. A variable region of the 28S ribosomal RNA gene was amplified with primers complementary to flanking sequences phylogenetically well conserved. The products of twelve animal DNAs (human, Japanese monkey, dog, cattle, pig, cat, rabbit, mouse, rat, chicken, frog, and fish) were separated by polyacrylamide gel electrophoresis, each revealing a few bands ranging from 150 to 100 base pairs. The band patterns obtained from each DNA sample differed in number and size, which indicates the applicability of the method to species identification. Samples containing either as little as 1 pg of DNA or degraded DNA of 0.2 to 0.5 kb in length were able to give detectable bands. Postmortem human tissue DNAs were tested as an example. They showed a pattern identical to the human control one, which was distinct from those of the other animals examined. 相似文献
75.
Threatening and otherwise inappropriate letters to members of the United States Congress 总被引:2,自引:0,他引:2
P E Dietz D B Matthews D A Martell T M Stewart D R Hrouda J Warren 《Journal of forensic sciences》1991,36(5):1445-1468
The authors examine the characteristics of threatening and otherwise inappropriate communications sent to members of the U.S. Congress by a sample of 86 subjects, 20 of whom threatened assassination. We quote excerpts from these letters and provide quantitative data on such variables as the volume, duration, form, and appearance of such communications; the enclosures; the subjects' perceived relationships to the recipients; the thematic content of the communications; and the messages and threats communicated. Comparisons between 43 subjects who pursued encounters with members of Congress and 43 who did not revealed 17 factors associated with such pursuit. In this population, threateners were significantly less likely to pursue an encounter than inappropriate letter writers who did not threaten, regardless of the type of threat or the harm threatened. Inappropriate letters to members of Congress are compared with those directed to Hollywood celebrities. Mentally disordered persons writing to public figures often mention and sometimes threaten public figures other than those to whom the letters are addressed, which raises important issues regarding notification of endangered third parties and the sharing of information among protective agencies. 相似文献
76.
R. CHRISTOPHER SPICER CIH CHMM HARRY J. GANGLOFF PH.D. Neil Feldscher CIH CSP 《环境索赔杂志》2005,17(1):13-28
Bioaerosol data is often used in cases of building mold infestation alleging damage or adverse health effects upon occupants, despite the lack of consistent sampling and analytical protocols and numerical health-based standards. The most fundamental problem in these scenarios is defining a “significant” difference between a suspect indoor environment and the reference environment, regardless of the type of sampling and analysis utilized. Data interpretation focused upon differences in absolute numerical concentrations of fungi is subject to wide differences in expert opinion. On the other hand, an objective quantification of differences can be expressed in terms of probability and better meets criteria established in evidentiary rules. 相似文献
77.
Toxicologic findings in the USS Iowa disaster. 总被引:5,自引:0,他引:5
The toxicologic results from the 47 victims of the explosion on the USS Iowa are presented. Good correlation between carboxyhemoglobin saturations and cause of death was found. There were no correlations between blood cyanide concentrations and causes of death. Volatile analysis suggested postmortem ethanol production rather than antemortem ethanol ingestion. No drugs except nicotine were detected in any of the victims. 相似文献
78.
The impact of high temperatures (24 to 39 degrees C) and low to moderately high humidities (20 to 70%) on the applicability of TLC systems for drug identification was studied during a 6 month climatologic cycle in Burkina Faso (West Africa). In general, the Rf values as observed on the plates were found to be substantially affected as compared with values obtained at temperate climates. Some TLC systems were more affected than others and the largest deviations of up to 30 Rf units were at low humidities. Tropical conditions also had a negative effect on the reproducibility of Rf values. However, when an Rf-correction procedure was applied, using reference mixtures of known drugs on each plate, accuracy as well as reproducibility of the resulting Rfc values were drastically improved and data thus corrected were found to be compatible with existing TLC data bases developed under moderate climatological conditions. The impact of high to extremely high humidities (70 to 100%) remains to be investigated. 相似文献
79.
In this study, a new method was developed for the impurity profiling of illicit MDMA tablets. The extraction efficiency, linearity, repeatability and reproducibility of the method were evaluated. Eighty two MDMA tablets coming from presumed unrelated large seizures in 2004 (n >500 tablets) were analyzed by gas chromatography mass spectrometry (GC-MS) in order to assess the discrimination power of the method. The latter was found to be practical, robust, relatively easy to perform, highly discriminative and yielding good chromatography. In addition, some new impurities were detected and identified. Their chemical structures and mass spectra are reported. 相似文献
80.
The role of the state is changing under the impact of, for example, globalization. The changes have been variously understood as the new public management (NPM), the hollowing–out of the state and the new governance. This special issue of Public Administration explores the changing role of the state in advanced industrial democracies. It focuses on the puzzle of why states respond differently to common trends.
This introductory article has three aims. First, we provide a brief review of the existing literature on public sector reform to show that our approach is distinctive. We argue that the existing literature does not explore the ways in which governmental traditions shape reform. Second, we outline an interpretive approach to the analysis of public sector reform built on the notions of beliefs, traditions, dilemmas and narratives. We provide brief illustrations of these ideas drawn from the individual country articles. Finally, we outline the ground covered by all the chapters but we do not summarize and compare their experiences of reform. That task is reserved for the concluding article. 相似文献
This introductory article has three aims. First, we provide a brief review of the existing literature on public sector reform to show that our approach is distinctive. We argue that the existing literature does not explore the ways in which governmental traditions shape reform. Second, we outline an interpretive approach to the analysis of public sector reform built on the notions of beliefs, traditions, dilemmas and narratives. We provide brief illustrations of these ideas drawn from the individual country articles. Finally, we outline the ground covered by all the chapters but we do not summarize and compare their experiences of reform. That task is reserved for the concluding article. 相似文献