首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   183篇
  免费   6篇
各国政治   17篇
工人农民   4篇
世界政治   18篇
外交国际关系   12篇
法律   84篇
中国政治   1篇
政治理论   50篇
综合类   3篇
  2023年   3篇
  2020年   2篇
  2019年   3篇
  2018年   5篇
  2017年   7篇
  2016年   6篇
  2015年   8篇
  2014年   6篇
  2013年   33篇
  2012年   7篇
  2011年   6篇
  2010年   6篇
  2009年   6篇
  2008年   7篇
  2007年   5篇
  2006年   3篇
  2005年   1篇
  2004年   11篇
  2003年   2篇
  2002年   3篇
  2001年   3篇
  2000年   3篇
  1999年   3篇
  1998年   10篇
  1997年   1篇
  1996年   4篇
  1995年   2篇
  1994年   2篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   4篇
  1988年   2篇
  1987年   4篇
  1986年   1篇
  1985年   1篇
  1984年   3篇
  1983年   1篇
  1982年   1篇
  1981年   2篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1976年   1篇
排序方式: 共有189条查询结果,搜索用时 15 毫秒
141.
142.
2,5,-Dimethoxy-4-bromoamphetamine (DOB) is of particular interest among the various "ecstasy" variants because there is an unusually long delay between consumption and effect, which dramatically increases the danger of accidental overdose in users. Screening for DOB in tablets is problematic because it is pharmacologically active at 0.2-3 mg, which is c. 50 times less than 3,4-methylenedioxy-N-methylamphetamine (MDMA) and makes it more difficult to detect in seized tablets using conventional spot tests. The normal Raman spectra of seized DOB tablets are dominated by the bands of the excipient with no evidence of the drug component. Here we report the first use of on-tablet surface-enhanced Raman spectroscopy (SERS) to enhance the signal from a low concentration drug. Raman studies (785-nm excitation) were carried on series of model DOB/lactose tablets (total mass c. 400 mg) containing between 1 mg and 15 microg of DOB and on seized DOB tablets. To generate surface-enhanced spectra, 5 microL of centrifuged silver colloid was dispensed onto the upper surface of the tablets, followed by 5 microL of 1.0 mol/dm(3) NaCl. The probe laser was directed onto the treated area and spectra accumulated for c. 20 sec (10 sec x 2). It was found that the enhancement of the DOB component in the model tablets containing 1 mg DOB/tablet and in the seized tablets tested was so large that their spectra were completely dominated by the vibrational bands of DOB with little or no contribution from the unenhanced lactose excipient. Indeed, the most intense DOB band was visible even in tablets containing just 15 microg of the drug. On-tablet surface-enhanced Raman spectroscopy is a simple method to distinguish between low dose DOB tablets and those with no active constituent. The fact that unique spectra are obtained allows identification of the drug while the lack of sample preparation and short signal accumulation times mean that the entire test can be carried out in <1 min.  相似文献   
143.
Validation of new methods   总被引:8,自引:0,他引:8  
Reliable analytical data are a prerequisite for correct interpretation of toxicological findings in the evaluation of scientific studies, as well as in daily routine work. Unreliable analytical data might not only be contested in court, but could also lead to unjustified legal consequences for the defendant or to wrong treatment of the patient. Therefore, new analytical methods to be used in forensic and/or clinical toxicology require careful method development and thorough validation of the final method. This is especially true in the context of quality management and accreditation, which have become matters of increasing relevance in analytical toxicology in recent years. In this paper, important considerations in analytical method validation will be discussed which may be used as guidance by scientists wishing to develop and validate analytical methods.  相似文献   
144.
Women who experience recurrent intimate partner violence (IPV) may use alcohol or drugs because they expect that these substances will help them cope with the negative physical and psychological sequelae of IPV. However, expectancies for alcohol and drug use have not been explored among this population of women. We used the Relaxation and Tension-Reduction Scale, Arousal and Aggression Scale, and Social Assertion Scale of the Alcohol Expectancy Questionnaire and modified its items to assess both alcohol and drug expectancies of 212 community-based, IPV-exposed women. Results of bivariate correlations showed that greater alcohol and drug expectancies were significantly correlated with greater alcohol problems and greater posttraumatic stress total and symptom severity scores. Results of a multivariate regression model showed that after controlling for demographic characteristics and history of childhood trauma, Relaxation and Tension- Reduction expectancies were associated with number of days of alcohol use, alcohol problems, physical and sexual IPV severity scores, and posttraumatic stress total and reexperiencing symptom severity scores. Expectancies do not significantly moderate the relationships between IPV, posttraumatic stress, and problematic alcohol and drug use. Given the strong relationships of expectancies with IPV severity, posttraumatic stress, and alcohol problems, expectancies may serve as targets for interventions to reduce alcohol use and problems and improve health-related outcomes in IPV-exposed women.  相似文献   
145.
The Role of Incubators in the Entrepreneurial Process   总被引:12,自引:4,他引:8  
We outline a model that improves our understanding of the role of incubators in the entrepreneurial process. Specifically, we focus on the impact of the services offered, namely infrastructure, coaching and networks, on the graduation rates of the respective incubators tenants. The model is tested among three different types of incubators, for-profit, non-profit, university-based incubators. Based on our qualitative findings, we conclude that our initial model is ineffective, in the sense that it cannot fully explain the role of the incubators in facilitating entrepreneurship. Interviews with directors of incubator centers were also carried out simultaneously. Further analysis of the results along with interview responses from incubator directors, led us to propose a more comprehensive model to explain how incubators affect the entrepreneurial process.  相似文献   
146.
147.
148.
Abstract: After only a few months in office, President Clinton launched a major review of government operations. The review, commonly known as the Gore Commission, looked at government-wide issues, as well as department- or agency-specific matters. The commission consulted a widely read book by David Osborne and Ted Gaebler and studied various government efforts at reform, both in the United States and elsewhere during the 1980s. Yet the process, if not the substance, of the review goes considerably beyond any of these. This paper looks at the work of the Gore Commission, reports briefly on its findings, and compares the review process adopted by Gore with other, earlier, efforts. It also identifies a series of “lessons learned” from the Gore Commission in the hope that they will be helpful to other governments should they contemplate undertaking similar reform measures. Sommaire: Quelques mois après son entrée en fonction, le président Clinton a lancé une vaste révision des opérations gouvernementales. Dans le cadre de cette révision, connue sous le titre de “ Commission Gore ”, on a examiné des questions à l'échelon de l'ensemble du gouvernement, ainsi que des questions concernant des ministères et des organismes précis. La commission a consulté le livre trés populaire de David Osborne et Ted Gaebler et étudia divers efforts de réforme gouvernementale, aux États-Unis et ailleurs, au cours des années 1980. Le processus, sinon la substance même de ce réexamen, va nettement au-delà de ces deux volets. Le présent article analyse le travail de la Commission Gore, rend compte brièvement de ses constatations et compare le processus de révision adopté par Gore avec d'autres efforts qui l'avaient précédé. Il definit également une série de “ leçons ”à tirer de la Commission Gore, dans l'espoir qu'elles seront utiles à d'autres gouvernements qui voudraient entreprendre de mesures de réforme similaires.  相似文献   
149.
Implementation has been used to try to explain too much, particularly that policy formulation should be oriented around implementation. The concentration on implementation has added little to our theoretical understanding of policymaking. Implementation studies have taken either "The Horrors of War" or "The Search for Theory" views. The latter has four major views, none of which is adequate. The best approach is to treat implementation as only one of a number of conditions which must be fulfilled for successful policymaking. The design perspection, explained in the paper, is the best approach for this.  相似文献   
150.
The combination of school finance reform, voter opposition to higher taxes, and rising costs forced the state of New Jersey to reorient its spending priorities. This article presents an analysis of budgetary data for the period FY 1990 to FY 1996, which clearly indicates that: 1) state resources were shifted from direct state services to state aid; 2) even though the 1991 sales and income tax hikes were revoked, the state's tax structure was more progressive in 1996 than in 1990; 3) Governor Florio's attempts to level down per pupil expenditures by reducing payments to wealthy school districts were largely stymied; 4) the proportion of state resources allocated to public education was lower in FY 1996 than the year preceding school finance reform; 5) because of education's reduced budget share, efforts to level up per pupil expenditures were severely circumscribed; and 6) state aid was diverted from homestead rebates to municipal aid.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号