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   904篇
  免费   62篇
各国政治   57篇
工人农民   77篇
世界政治   193篇
外交国际关系   72篇
法律   407篇
中国政治   13篇
政治理论   142篇
综合类   5篇
  2023年   17篇
  2022年   6篇
  2021年   12篇
  2020年   38篇
  2019年   36篇
  2018年   48篇
  2017年   56篇
  2016年   51篇
  2015年   39篇
  2014年   33篇
  2013年   105篇
  2012年   52篇
  2011年   34篇
  2010年   44篇
  2009年   31篇
  2008年   42篇
  2007年   50篇
  2006年   47篇
  2005年   38篇
  2004年   25篇
  2003年   18篇
  2002年   32篇
  2001年   16篇
  2000年   8篇
  1999年   6篇
  1998年   8篇
  1997年   7篇
  1996年   3篇
  1995年   5篇
  1994年   5篇
  1993年   1篇
  1992年   3篇
  1991年   4篇
  1990年   3篇
  1989年   1篇
  1988年   5篇
  1987年   1篇
  1986年   5篇
  1985年   6篇
  1984年   4篇
  1983年   5篇
  1982年   5篇
  1981年   2篇
  1978年   4篇
  1977年   2篇
  1975年   1篇
  1974年   1篇
  1967年   1篇
排序方式: 共有966条查询结果,搜索用时 31 毫秒
21.
22.
The paper investigates party-union relationships in Italy (1946–2014) by hand-coding parties’ parliamentary speeches and trade unions’ congress motions. In line with the cartel party thesis, a time series analysis shows that the ideological closeness between the left-wing Italian General Confederation of Labour and left-wing parties deteriorated when the Italian Socialist Party (1980) and the heirs of the Italian Communist Party (1998) converged toward the centre of the ideological spectrum. Conversely, the closeness between the Catholic-inspired Italian Confederation of Workers’ Unions and the heirs of Christian Democracy increased after 1994, when the former party’s leftist factions became the major part of the Italian Popular Party.  相似文献   
23.
Journal of Youth and Adolescence - Asian Americans are simultaneously stereotyped as a perpetual foreigner and a model minority. This cross-sectional study of 308 Filipino American youth (mean age...  相似文献   
24.
Chioqueta AP  Stiles TC 《危机》2007,28(2):67-73
In this study we examined the role of psychological buffers (life satisfaction, self-esteem, perception of family cohesion, and perception of social support) in the development of hopelessness and suicidal ideation. The participants were 314 university students, 71 males and 243 females, who were asked to complete a battery of instruments measuring the psychological buffers mentioned above. The results of a set of hierarchical multiple regression analyses suggested that life satisfaction and self-esteem are independent predictors of lower levels of hopelessness, while perception of social support seems to be the major predictor of lower levels of suicidal ideation independent of depression and hopelessness severity. Thus, hopelessness seems to be minimized by the level of life satisfaction and level of self-esteem exhibited by the individuals, while the key factor to the mitigation of suicidal ideas seems to be perception of social support.  相似文献   
25.
26.
Park A 《Time》2007,169(16):51-52
  相似文献   
27.
28.
Park A 《Time》2007,169(5):114-115
  相似文献   
29.
Park A 《Time》2007,170(21):55
  相似文献   
30.
Ammonium nitrate fuel oil is an explosive mixture found in most antipersonnel landmines (APL) buried throughout the Colombian territory. During more than 50 years of internal conflict, the Colombian government has found that trained dogs are the most effective method to detect APL. However, the olfactive signature in ANFO is unknown and also if there are differences in detection related to the explosive manufacturing origin. Therefore, this work begins with the analytical validation of the method used to determine ammonia, in its derivatized form as carbamate, released by home-made ANFO using HS-SPME-GC-FID. Once validated, the method was used to identify ammonia and other organic volatile compounds present in ANFO, under laboratory and simulated field conditions. The validation process includes the evaluation of the optimum conditions for the derivation and extraction of butylcarbamate, the determination of the working ranges with linear response in FID, the limits of detection and quantification, the sensitivity, and the precision. The results of the validation established linearity and sensitivity in a concentration between 20 and 120 mg/L, as well as low limits of detection and quantification of 6.4 and 21.4 mg/L, respectively. Also, an intermediate precision of 11% for butylcarbamate with a repeatability of 8%. The validated method showed in real samples of home-made ANFO besides ammonia, the presence of low molecular methylamines, and also exhibited differences in volatile compositions according to the origin. The objective of this work is to offer a reliable analytical methodology for the extraction and analysis of volatile compounds from ANFO.  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