全文获取类型
收费全文 | 180篇 |
免费 | 7篇 |
专业分类
各国政治 | 4篇 |
工人农民 | 4篇 |
世界政治 | 47篇 |
外交国际关系 | 5篇 |
法律 | 66篇 |
中国政治 | 1篇 |
政治理论 | 60篇 |
出版年
2022年 | 1篇 |
2021年 | 1篇 |
2020年 | 5篇 |
2019年 | 5篇 |
2018年 | 6篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 7篇 |
2014年 | 4篇 |
2013年 | 34篇 |
2012年 | 2篇 |
2011年 | 3篇 |
2010年 | 3篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 2篇 |
1990年 | 3篇 |
1989年 | 7篇 |
1987年 | 4篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有187条查询结果,搜索用时 31 毫秒
91.
Investigates the attitudes of local public administrators in the metropolitan area of a southwestern state toward merit-related issues. Findings show the effects of demographic, partisan, ethnic, and educational characteristics on the perceptions of city and county supervisors. Assesses the implications of differential perceptions for program implementation and proposes research hypotheses as a guide for further inquiry. 相似文献
92.
This study is the first reported ion mobility detection of ethyl centralite and diphenylamine (DPA) smokeless gunpowder stabilizers, together with the nitroso and nitro derivatives of diphenylamine. First, the applicability of the ion mobility spectrometry (IMS) for the substances of interest was determined. The existence of numerous peaks, both in positive and negative modes, clearly demonstrates the success of these experiments. All mono and di-nitro derivatives of DPA tested were detected with this method. Unfortunately, many of the ions generated were not accurately identified. However, reduced mobility constants representative of each ion generated under defined operating conditions could be used for purpose of compound identification. The method was then successfully tested on real gunpowder samples. By the use of IMS, we managed to establish a rapid, simple and sensitive screening method for the detection and identification of smokeless gunpowder organic components. 相似文献
93.
94.
95.
96.
Kirsten Retief M.S. Adam G. West Ph.D. Michèle F. Pfab M.S. 《Journal of forensic sciences》2014,59(6):1541-1551
Cycads in South Africa are facing an extinction crisis due to the illegal extraction of plants from the wild. Proving wild origin of suspect ex situ cycads to the satisfaction of a court of law is difficult, limiting law enforcement efforts. We investigated the feasibility of using multiple stable isotopes to identify specimens removed from the wild. Relocated and wild specimens from two species in the African genus Encephalartos (E. lebomboensis and E. arenarius) were sampled. 14C analysis indicated that a ± 30‐year chronology could be reliably obtained from the cycads. For E. arenarius, pre‐relocation tissue was consistent with a wild origin, whereas tissue grown post‐relocation was isotopically distinct from the wild for 87Sr/86Sr and δ15N. For E. lebomboensis, δ34S, δ18O, and 87Sr/86Sr were different between relocated and control plants, consistent with the >30 years since relocation. Our findings demonstrate the potential for a forensic isotope approach to identify illegal ex situ cycads. 相似文献
97.
Thomas G. West 《Society》2013,50(5):472-476
98.
99.
100.