全文获取类型
收费全文 | 12887篇 |
免费 | 334篇 |
专业分类
各国政治 | 824篇 |
工人农民 | 326篇 |
世界政治 | 1066篇 |
外交国际关系 | 633篇 |
法律 | 6924篇 |
中国共产党 | 1篇 |
中国政治 | 53篇 |
政治理论 | 3230篇 |
综合类 | 164篇 |
出版年
2020年 | 131篇 |
2019年 | 178篇 |
2018年 | 247篇 |
2017年 | 275篇 |
2016年 | 309篇 |
2015年 | 218篇 |
2014年 | 268篇 |
2013年 | 1685篇 |
2012年 | 340篇 |
2011年 | 357篇 |
2010年 | 291篇 |
2009年 | 299篇 |
2008年 | 373篇 |
2007年 | 420篇 |
2006年 | 370篇 |
2005年 | 315篇 |
2004年 | 340篇 |
2003年 | 333篇 |
2002年 | 337篇 |
2001年 | 404篇 |
2000年 | 383篇 |
1999年 | 306篇 |
1998年 | 204篇 |
1997年 | 197篇 |
1996年 | 183篇 |
1995年 | 159篇 |
1994年 | 160篇 |
1993年 | 160篇 |
1992年 | 224篇 |
1991年 | 262篇 |
1990年 | 229篇 |
1989年 | 238篇 |
1988年 | 219篇 |
1987年 | 225篇 |
1986年 | 243篇 |
1985年 | 176篇 |
1984年 | 191篇 |
1983年 | 195篇 |
1982年 | 141篇 |
1981年 | 122篇 |
1980年 | 104篇 |
1979年 | 151篇 |
1978年 | 107篇 |
1977年 | 107篇 |
1976年 | 80篇 |
1975年 | 90篇 |
1974年 | 106篇 |
1973年 | 110篇 |
1972年 | 89篇 |
1971年 | 67篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
942.
943.
944.
John Mulroy 《Family Court Review》2011,49(3):657-670
A new educational trend has developed over the past decade that may actually be doing more harm to high school students than good. States have been passing legislation requiring high school students to complete a college prep‐level curriculum in order to receive a high school diploma. While this push for higher academic achievement is a great idea, students are not given the educational base they need to be able to succeed in such a program once they reach high school and many are left without the skills necessary to handle such academic expectations. This Note proposes guidelines for changing these rigid state statutes in favor of a Three‐Tiered System that gives students options based on their academic abilities and urges states to adopt these changes. 相似文献
945.
Wesley G. Skogan 《犯罪学与公共政策》2011,10(4):987-990
946.
947.
Claire E.V. French Cynthia G. Jensen Susan K. Vintiner Douglas A. Elliot Susan R. McGlashan 《Forensic Science International Supplement Series》2008,178(1):1-6
There are a number of forensic cases in which the identification of the epithelial cell type from which DNA originated would provide important probative evidence. This study aimed to develop a technique using histological staining of fixed cells to distinguish between skin, buccal and vaginal epithelium. First, 11 different stains were screened on formalin-fixed, wax-embedded cells from five women. Samples were analysed qualitatively by examining staining patterns (colour) and morphology (absence or presence of nuclei). Three of the staining methods – Dane's, Csaba's and Ayoub-Shklar – were successful in distinguishing skin epithelial cells from buccal and vaginal. Second, cells were smeared directly onto slides, fixed with one of five fixatives and stained with one of the three stains mentioned above. Methanol fixation, coupled with the Dane's staining method, specific to keratin, was the only technique that distinguished between all three cell types. Skin cells stained magenta, red and orange and lacked nuclei; buccal cells stained predominantly orange–pink with red nuclei; while vaginal cells stained bright orange with orange nuclei and a blue extracellular hue. This staining pattern in vaginal cells was consistent in samples collected from 50 women aged between 18 and 67. Identification of cell type from unlabelled micrographs by 10 trained observers showed a mean success rate of 95%. The results of this study demonstrate that histological staining may provide forensic scientists with a technique for distinguishing between skin, buccal and vaginal epithelial cells and thus would enable more conclusive analyses when investigating sexual assault cases. 相似文献
948.
Managing incidental findings in human subjects research: analysis and recommendations. 总被引:8,自引:8,他引:0
Susan M Wolf Frances P Lawrenz Charles A Nelson Jeffrey P Kahn Mildred K Cho Ellen Wright Clayton Joel G Fletcher Michael K Georgieff Dale Hammerschmidt Kathy Hudson Judy Illes Vivek Kapur Moira A Keane Barbara A Koenig Bonnie S Leroy Elizabeth G McFarland Jordan Paradise Lisa S Parker Sharon F Terry Brian Van Ness Benjamin S Wilfond 《The Journal of law, medicine & ethics》2008,36(2):219-48, 211
No consensus yet exists on how to handle incidental findings (IFs) in human subjects research. Yet empirical studies document IFs in a wide range of research studies, where IFs are findings beyond the aims of the study that are of potential health or reproductive importance to the individual research participant. This paper reports recommendations of a two-year project group funded by NIH to study how to manage IFs in genetic and genomic research, as well as imaging research. We conclude that researchers have an obligation to address the possibility of discovering IFs in their protocol and communications with the IRB, and in their consent forms and communications with research participants. Researchers should establish a pathway for handling IFs and communicate that to the IRB and research participants. We recommend a pathway and categorize IFs into those that must be disclosed to research participants, those that may be disclosed, and those that should not be disclosed. 相似文献
949.
P. Snchez-Diz P.G. Menounos A. Carracedo I. Skitsa 《Forensic Science International: Genetics Supplement Series》2008,2(4):e71-e72
Allele frequencies for 16 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818, FGA, and SE33) were calculated for a sample of 300 unrelated individuals from Greece. No deviations from Hardy–Weinberg equilibrium were observed for all loci. The combined power of discrimination (PD) and the combined power of exclusion (PE) for the 16 tested STR loci were 0.999999999 and 0.999999816, respectively. Population comparisons were carried out and low genetic distances were found between our data and those previously published for other neighbouring European populations. 相似文献
950.
While rural poverty is endemic in the Andean region, structural adjustment programmes have led to a dismemberment of agricultural research and extension services so that they are unable to serve the needs of smallholder farmers. The NGO Practical Action has been working in the Andes to address farmers' veterinary and agriculture needs. The work has included the training of farmer-to-farmer extension agents, known locally as Kamayoq. The Kamayoq have encouraged farmer participatory research, and local farmers pay them for their veterinary and crop advisory services in cash or in kind. The Kamayoq model is largely an unsubsidised approach to the provision of appropriate technical services and encouragement of farmer participation. The model also illustrates that, in the context of encouraging farmer participation and innovation, NGOs have advantages over research organisations because of their long-term presence, ability to establish trust with local farmers, and their emphasis on social and community processes. 相似文献