全文获取类型
收费全文 | 22850篇 |
免费 | 896篇 |
专业分类
各国政治 | 998篇 |
工人农民 | 841篇 |
世界政治 | 1837篇 |
外交国际关系 | 785篇 |
法律 | 14205篇 |
中国共产党 | 2篇 |
中国政治 | 107篇 |
政治理论 | 4766篇 |
综合类 | 205篇 |
出版年
2020年 | 343篇 |
2019年 | 391篇 |
2018年 | 476篇 |
2017年 | 559篇 |
2016年 | 590篇 |
2015年 | 457篇 |
2014年 | 491篇 |
2013年 | 2310篇 |
2012年 | 532篇 |
2011年 | 569篇 |
2010年 | 508篇 |
2009年 | 566篇 |
2008年 | 572篇 |
2007年 | 592篇 |
2006年 | 571篇 |
2005年 | 521篇 |
2004年 | 540篇 |
2003年 | 529篇 |
2002年 | 489篇 |
2001年 | 898篇 |
2000年 | 808篇 |
1999年 | 682篇 |
1998年 | 362篇 |
1997年 | 298篇 |
1996年 | 268篇 |
1995年 | 273篇 |
1994年 | 314篇 |
1993年 | 294篇 |
1992年 | 455篇 |
1991年 | 483篇 |
1990年 | 432篇 |
1989年 | 469篇 |
1988年 | 415篇 |
1987年 | 452篇 |
1986年 | 434篇 |
1985年 | 444篇 |
1984年 | 366篇 |
1983年 | 402篇 |
1982年 | 318篇 |
1981年 | 302篇 |
1980年 | 223篇 |
1979年 | 334篇 |
1978年 | 230篇 |
1977年 | 191篇 |
1976年 | 174篇 |
1975年 | 161篇 |
1974年 | 181篇 |
1973年 | 162篇 |
1972年 | 147篇 |
1971年 | 121篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
941.
942.
Tracy M. Scull Janis B. Kupersmidt Alison E. Parker Kristen C. Elmore Jessica W. Benson 《Journal of youth and adolescence》2010,39(9):981-998
Two cross-sectional studies investigated media influences on adolescents’ substance use and intentions to use substances in
the context of exposure to parental and peer risk and protective factors. A total of 729 middle school students (n = 351, 59% female in Study 1; n = 378, 43% female in Study 2) completed self-report questionnaires. The sample in Study 1 was primarily African-American
(52%) and the sample in Study 2 was primarily Caucasian (63%). Across the two studies, blocks of media-related cognitions
made unique contributions to the prediction of adolescents’ current substance use and intentions to use substances in the
future above and beyond self-reported peer and parental influences. Specifically, identification with and perceived similarity
to media messages were positively associated with adolescents’ current substance use and intentions to use substances in the
future, and critical thinking about media messages and media message deconstruction skills were negatively associated with
adolescents’ intention to use substances in the future. Further, peer influence variables (e.g., peer pressure, social norms,
peer substance use) acted as risk factors, and for the most part, parental influence variables (e.g., parental pressure to
not use, perceived parental reaction) acted as protective factors. These findings highlight the importance of developing an
increased understanding of the role of media messages and media literacy education in the prevention of substance use behaviors
in adolescence. 相似文献
943.
Oscar W. Gabriel Ulf Bohmann Daniel Gaus Emanuel Richter Annika Frisch Helga Haftendorn Dirk Berg-Schlosser Frank Bönker Dennis-Jonathan Mann Christian Tuschhoff Karsten Schmitz Jared Sonnicksen Heinrich Pehle Marco Schäferhoff Wilhelm Bleek Jürgen Petersen 《Politische Vierteljahresschrift》2009,50(3):646-690
944.
945.
946.
Klaus-Gert Lutterbeck Armin Schäfer Andreas Heyer Christian Kaiser Helga Haftendorn Sandra Seubert Christian Bala Ralf J. Leiteritz Frank Dietrich Christian Brütt Christian Reisinger Alexander Warkotsch Mandana Biegi Burkhard Conrad Christian Stecker 《Politische Vierteljahresschrift》2009,50(2):327-363
Ohne Zusammenfassung 相似文献
947.
948.
A positive, statistical and economic significant relation between growth, income level and the Economic Freedom of the World (EFW) index has been amply documented. Most analyses, however, use OLS methods which, in the presence of endogenous variables do not establish causality and produce biased and inconsistent estimates. This paper uncovers the exogenous component of EFW using IV methods and finds a robust channel from economic freedom to prosperity. The findings, including instrument validity tests, support the importance of policies and institutions for development and warrants policy advice aimed at increasing economic freedom to foster prosperity. 相似文献
949.
The riskiness of state employee pension plan portfolios varies across states. We investigate whether this variation is related to how public employees and taxpayers share actuarial surpluses of pension accounts. We focus on two determinants of a plan’s asset mix: the relative influence of public employees to taxpayers; and whether a surplus-sharing contract is specified. Our theoretical model demonstrates that the effect of public employee influence on the asset mix is ambiguous. Our empirical results corroborate this complex theoretical result. In our theoretical and empirical analyses, if a surplus sharing rule is specified, plans adopt a more aggressive investment allocation. 相似文献
950.
Michael J. Ensley 《Public Choice》2009,138(1-2):221-238
Individual citizens are the largest source of contributions for congressional candidates in the United States. This paper investigates if and how fundraising from this source is related to the ideological positions of candidates. Specifically, we ask whether the amount of contributions depends on: (1) the extremity of candidate ideology; and (2) the level of candidate divergence in the same race. These results have important implications for candidate positioning strategies, as well as for evaluating the effects of recent campaign finance reforms. 相似文献