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   17276篇
  免费   1223篇
各国政治   698篇
工人农民   830篇
世界政治   1127篇
外交国际关系   529篇
法律   12185篇
中国共产党   2篇
中国政治   104篇
政治理论   2935篇
综合类   89篇
  2023年   76篇
  2021年   86篇
  2020年   427篇
  2019年   444篇
  2018年   562篇
  2017年   577篇
  2016年   656篇
  2015年   503篇
  2014年   532篇
  2013年   1787篇
  2012年   481篇
  2011年   500篇
  2010年   532篇
  2009年   556篇
  2008年   506篇
  2007年   499篇
  2006年   518篇
  2005年   432篇
  2004年   429篇
  2003年   352篇
  2002年   402篇
  2001年   671篇
  2000年   602篇
  1999年   479篇
  1998年   237篇
  1997年   171篇
  1996年   191篇
  1995年   189篇
  1994年   168篇
  1993年   175篇
  1992年   303篇
  1991年   311篇
  1990年   294篇
  1989年   275篇
  1988年   304篇
  1987年   261篇
  1986年   320篇
  1985年   316篇
  1984年   246篇
  1983年   226篇
  1982年   177篇
  1981年   154篇
  1980年   143篇
  1979年   219篇
  1978年   115篇
  1977年   91篇
  1975年   94篇
  1974年   124篇
  1973年   79篇
  1972年   78篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
861.
Relationships among major life events, perceived social support, and psychological disorder were assessed in a sample of older adolescents. Negative life events and satisfaction with social support were significantly and independently related to a range of psychological symptoms. Further, the relationship between negative events and disorder was moderated by gender, the types of events experienced, and anticipated change in the psychosocial environment. The importance of the use of standardized and psychometrically sound measures of life events, social support, and psychological disorder is highlighted.Received his Ph.D. from UCLA in 1980. An assistant professor, he is currently investigating stress and coping among children and adolescents.Received her Ph.D. from the University of Vermont in 1985. An assistant professor, she is currently studying social support.Received Ed. M. from Harvard Universtiy. He is a doctoral student in clinical psychology interested in the role of social support in coping with stress during adolescence.Received her BA from the University of Vermont. She is a doctoral student in clinical psychology.  相似文献   
862.
Over the past two decades states have significantly increased their use of competitive bidding to purchase health and social services from private agencies. Competitive contracting is thought to facilitate program administration, to reduce costs, and to increase the quality of delivered services. We evaluate these claims in light of Massachusetts' experience with competitive contracting for mental health care. We find that few of the expected benefits are achieved. In practice, supposedly competitive bidding systems often degenerate into administratively complicated negotiations between the state and private monopolies. This results in higher costs and lower quality of services. In light of this negative assessment, three strategies for reform are proposed and evaluated.  相似文献   
863.
864.
865.
Sixty-eight college students listed the factors they consider or would consider when making the following commitments: choosing courses, choosing a major, choosing a career, choosing a friend, choosing a romantic partner, and choosing a lifelong partner. In addition, subjects provided their own definition ofcommitment in an unstructured essay. Subjects listed more factors, more distinct types of factors, and more original factors for interpersonal commitments than for academic/vocational commitments. There were few gender differences found in these measures, contradicting the idea that men and women think differently about different commitments. In addition, few gender or class year differences were found in the themes present in the essay definingcommitment. Conceptions of commitment, as described in essays, predicted thinking about specific commitments only slightly.Received Ph.D. in Psychology and M.S.E. in Computer Science from the University of Pennsylvania, and has research interests in the areas of cognitive development and reasoning and decision making.Received Ph.D. in Counseling and Guidance from the University of Wisconsin, Madison, and has research interests in adolescent development and adolescent psychopathology.  相似文献   
866.
In an attempt to delay hatching without affecting their viability, the eggs ofLatheticus oryzae W. were subjected to cold treatment at 5° for varying periods and at different stages of their development. A small dose of 0.5 krad of gamma radiation was also given at each of those temperature treatments. Most of the eggs hatched at 30° following low-temperature exposures of 1 and 2 days. There was a significant decrease in hatch as the exposure period increased further (P<0.05). An egg exposure to 5° also led to an increase in egg period and the increase was nearly equal to the period of cold exposure. Radiation did not alter the situation.
Zusammenfassung Kühllagerung ist eine der gebr?uchlichsten Methoden für die Aufbewahrung von Insekteneiern. Um die optimalen Bedingungen für eine Vorratshaltung zu bestimmen, wurden 0–1 d alte Eier vonL. oryzae Temperaturen von 5° w?hrend 1–7 d ausgesetzt, nachdem sie verschieden lange bei 30° gehalten waren. Eine kleine Dosis von 0.5 krad Gammabestrahlung wurde bei jeder Temperaturbehandlung ebenfalls gegeben. Alle Eiproben wurden nach den verschiedenen K?ltebehandlungen in 30° zurückgebracht und die Wirkung auf Schlüpfprozentsatz und Eidauer bestimmt. Die Eidauer nahm zu, wenn die Eier bei 5° gehalten wurden, was anzeigt, da? die Embryogenese bei 5° unterdrückt wurde. Die Lebensf?higkeit der Eier wurde nicht beeintr?chtigt bei einer 5°-Einwirkungsdauer von 2 d, nahm aber bei weiterer Verl?ngerung der Expositionsdauer ab. Nur etwa 37% der Eier schlüpften (44,1% der Kontrolleier) nach 7-t?giger K?ltebehandlung. Bestrahlung beeinflu?te weder das Schlüpfen noch die Entwicklungsdauer.
  相似文献   
867.
In 1982, disabled workers who came on the social security disability insurance rolls from mid-1980 to mid-1981 had median monthly incomes of less than $500 if they were unmarried and less than $1,300 if they were married. These median monthly income levels, which include the income of a spouse and minor children if present, are roughly half those of the noninstitutionalized population aged 25-64. Social security benefits are the most important source of income for disabled workers and their families: They account for 40 percent of the total family income of married disabled workers and 65 percent of the total income of unmarried disabled workers. Social security benefits provide at least half of all income for more than 80 percent of unmarried disabled-worker beneficiaries and for 50 percent of the married beneficiaries. For married disabled-worker beneficiaries, earnings of the spouse are the second most important income source. Spousal earnings account for 28 percent of total income. Pensions and asset income each account for about 10 percent of total income for these married beneficiaries. Earnings are not an important source of income for unmarried disabled-worker beneficiaries for whom they amount to only about 3 percent of total income. Pensions, asset income, and public transfers each account for about 10 percent of total income of the unmarried beneficiaries.  相似文献   
868.
869.
870.
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