全文获取类型
收费全文 | 19601篇 |
免费 | 551篇 |
专业分类
各国政治 | 905篇 |
工人农民 | 734篇 |
世界政治 | 1693篇 |
外交国际关系 | 755篇 |
法律 | 11181篇 |
中国共产党 | 2篇 |
中国政治 | 86篇 |
政治理论 | 4550篇 |
综合类 | 246篇 |
出版年
2021年 | 103篇 |
2020年 | 251篇 |
2019年 | 296篇 |
2018年 | 410篇 |
2017年 | 459篇 |
2016年 | 508篇 |
2015年 | 339篇 |
2014年 | 391篇 |
2013年 | 2064篇 |
2012年 | 486篇 |
2011年 | 510篇 |
2010年 | 399篇 |
2009年 | 454篇 |
2008年 | 525篇 |
2007年 | 558篇 |
2006年 | 502篇 |
2005年 | 480篇 |
2004年 | 476篇 |
2003年 | 480篇 |
2002年 | 449篇 |
2001年 | 748篇 |
2000年 | 681篇 |
1999年 | 556篇 |
1998年 | 329篇 |
1997年 | 286篇 |
1996年 | 250篇 |
1995年 | 246篇 |
1994年 | 283篇 |
1993年 | 249篇 |
1992年 | 372篇 |
1991年 | 406篇 |
1990年 | 366篇 |
1989年 | 379篇 |
1988年 | 344篇 |
1987年 | 347篇 |
1986年 | 357篇 |
1985年 | 351篇 |
1984年 | 308篇 |
1983年 | 335篇 |
1982年 | 280篇 |
1981年 | 273篇 |
1980年 | 205篇 |
1979年 | 258篇 |
1978年 | 178篇 |
1977年 | 154篇 |
1976年 | 137篇 |
1975年 | 131篇 |
1974年 | 145篇 |
1973年 | 123篇 |
1972年 | 116篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
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
65.
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
66.
Edward J. Keall 《British Journal of Middle Eastern Studies》2005,32(2):249-292
67.
68.
69.
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
70.
Washington University v. Catalona revolves around ownership of tissue samples provided by patients for research purposes, raising significant ethical and legal questions concerning patient rights, current human research practices, and the treatment of samples as capital resources by the research institution. 相似文献