全文获取类型
收费全文 | 210篇 |
免费 | 9篇 |
专业分类
各国政治 | 10篇 |
工人农民 | 14篇 |
世界政治 | 51篇 |
外交国际关系 | 12篇 |
法律 | 108篇 |
政治理论 | 24篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 9篇 |
2016年 | 2篇 |
2015年 | 6篇 |
2014年 | 5篇 |
2013年 | 27篇 |
2012年 | 9篇 |
2011年 | 10篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 15篇 |
2007年 | 11篇 |
2006年 | 9篇 |
2005年 | 24篇 |
2004年 | 9篇 |
2003年 | 14篇 |
2002年 | 15篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 4篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
排序方式: 共有219条查询结果,搜索用时 0 毫秒
81.
82.
83.
84.
85.
Bret L. Billet Jan Knippers Black Daniel H. Levine Maristella Botticini Allan C. Reddy Lawrence S. Graham Harvey Glickman Fred H. Lawson Thomas U. Berger Paul W. Kuznets Yuan-li Wu Marianne A. Ferber Stephen P. Mumme Dilmus D. James Alison Brysk Carrie A. Meyer Juan M. del Aguila Robert W. Anderson Walter C. Opello M. C. Hallberg Luth Tweenten Anderson Professor 《Studies in Comparative International Development (SCID)》1994,29(3):84-126
86.
87.
One hundred and fifty-five cord cells were tested for the red blood cell antigens Lua, Lub and Cob in order to collect data on the early postnatal expression of these markers. Additionally, dosage studies were carried out in 8–10-month-old heterozygous children. Antigens Lua and Lub revealed to be significantly less expressed in children of both ages compared with those of their mothers, whereas no such differences could be demonstrated in the expression of the antigen Cob. 相似文献
88.
The resilience of autocratic regimes in various world regions and the emerging model of illiberal capitalist autocracies (China, Russia) have led scholars to shift their attention to the durability of such regimes. Autocracies not only resist the global spread of democracy, but are developing their own domestic efforts in the promotion of autocracy. This study argues that processes at the regional level aim at the dissemination and diffusion of autocratic norms, structures, processes, policy approaches or practices. Likewise, we propose that authoritarian gravity centres can be attributed with both the active promotion of autocracy as well as the inducement of diffusion effects. Our research tries to shed some light on their strategies and modes of influence on countries in their geopolitical proximity (target states). 相似文献
89.
Amber R. Rose MSFS Monica Joshi PhD Marianne E. Staretz PhD Matthew Wood PhD Thomas A. Brettell PhD 《Journal of forensic sciences》2023,68(4):1148-1161
Aminoindanes are a class of novel psychoactive substances (NPSs) that have become more prevalent over the past decade. GC–MS is often utilized for identifying seized drugs and is well regarded for its ability to separate mixtures. However, certain aminoindanes have similar mass spectral data and require specific gas chromatographic stationary phases for separation. Derivatization is an alternative method that can be applied to GC–MS to enhance chromatographic results, providing more selective analysis in seized-drug identification. This study investigates derivatization techniques to provide options for forensic science laboratories in accurately identifying aminoindanes. Three derivatization reagents, N-methyl-bis(trifluoroacetamide) (MBTFA), heptafluorobutyric anhydride (HFBA), and ethyl chloroformate (ECF) were evaluated for the analysis of eight aminoindanes by GC–MS using two common gas chromatographic stationary phases, Rxi®-5Sil MS and Rxi®-1Sil MS. All three derivatization methods successfully isolated eight aminoindanes, including the isomers 4,5-methylenedioxy-2-aminoindane (4,5-MDAI), and 5,6-methylenedioxy-2-aminoindane (5,6-MDAI) that could not be differentiated prior to derivatization. Reduced peak tailing and increased abundance were observed after derivatization for all the compounds, and mass spectra of the derivatives contained individualizing fragment ions that allowed for further characterization of the aminoindanes. This excluded 4,5-MDAI and 5,6-MDAI as they shared the same characteristic ions and were only distinguishable by their retention times. All three derivatization techniques used in this study allow for successful characterization of the aminoindanes and give forensic science laboratories flexibility in their analysis approach when they encounter these compounds. 相似文献
90.
Though reasonable people may argue about whether cable television and local telephone services are natural monopolies in theory, historically they have developed with infrastructures that make them more likely to have important declining cost characteristics in reality. Additionally, common carriage issues, especially for telephones, may necessitate regulatory oversight. Though touted as deregulation, and certainly eliminating many cross‐industry barriers, the Telecommunications Act of 1996 is better understood as reregulation. The act maintains a common carriage philosophy while attempting to promote competition. However, evidence indicates it is unlikely that the new regulatory regime will result in efficient prices or true competition. Instead, duopoly in cable and oligopoly in telephony are probably the best that can be achieved under the act. 相似文献