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   7244篇
  免费   479篇
各国政治   335篇
工人农民   227篇
世界政治   476篇
外交国际关系   288篇
法律   5056篇
中国政治   35篇
政治理论   1270篇
综合类   36篇
  2020年   158篇
  2019年   172篇
  2018年   185篇
  2017年   217篇
  2016年   221篇
  2015年   206篇
  2014年   189篇
  2013年   759篇
  2012年   155篇
  2011年   180篇
  2010年   208篇
  2009年   223篇
  2008年   167篇
  2007年   161篇
  2006年   169篇
  2005年   160篇
  2004年   178篇
  2003年   157篇
  2002年   139篇
  2001年   310篇
  2000年   252篇
  1999年   225篇
  1998年   98篇
  1997年   65篇
  1996年   70篇
  1995年   80篇
  1994年   87篇
  1993年   87篇
  1992年   153篇
  1991年   160篇
  1990年   147篇
  1989年   157篇
  1988年   123篇
  1987年   141篇
  1986年   125篇
  1985年   133篇
  1984年   103篇
  1983年   118篇
  1982年   86篇
  1981年   81篇
  1980年   56篇
  1979年   108篇
  1978年   70篇
  1977年   58篇
  1976年   50篇
  1975年   47篇
  1974年   55篇
  1973年   55篇
  1972年   44篇
  1968年   40篇
排序方式: 共有7723条查询结果,搜索用时 15 毫秒
741.
A novel method for the forensic analysis of commercial petroleum products is presented. In this approach, the petroleum sample is extracted with nitromethane and then separated by capillary liquid chromatography with laser-induced fluorescence detection. The addition of selective fluorescence quenching agents allows the sample to be profiled by the distribution of alternant and nonalternant polycyclic aromatic hydrocarbons (PAHs). In preliminary studies, the quenching behavior of nitromethane and diisopropylamine was established by using a standard mixture of sixteen PAHs ranging in size from two to six aromatic rings. Subsequent examination of new and used motor oil demonstrated that characteristic differences arise in the PAH content, which may allow for the unique identification of oil from a particular engine or vehicle. In addition, three brands of petrolatum jelly were successfully distinguished. Although a number of alternant alkylated and heterocyclic PAHs were found in all petrolatum samples, there were significant differences in the relative concentrations of alternant as well as nonalternant PAHs. This allowed for clear differentiation of the samples through qualitative inspection of their chromatograms as well as quantitative statistical correlation techniques.  相似文献   
742.
743.
744.
745.
746.
One long‐recognized consequence of the tension between popular sovereignty and democratic values like liberty and equality is public opinion backlash, which occurs when individuals recoil in response to some salient event. For decades, scholars have suggested that opinion backlash impedes policy gains by marginalized groups. Public opinion research, however, suggests that widespread attitude change that backlash proponents theorize is likely to be rare. Examining backlash against gays and lesbians using a series of online and natural experiments about marriage equality, and large‐sample survey data, we find no evidence of opinion backlash among the general public, by members of groups predisposed to dislike gays and lesbians, or from those with psychological traits that may predispose them to lash back. The important implication is that groups pursuing rights should not be dissuaded by threats of backlash that will set their movement back in the court of public opinion.  相似文献   
747.
748.
Abstract

This paper provides a comprehensive evaluation of market segmentation and lender/purchaser specialization in the primary and secondary mortgage markets. It describes and assesses the 1990 Home Mortgage Disclosure Act (HMDA) data, which for the first time provide detailed information on the borrower and neighborhood racial and income characteristics of mortgage loan originations and securitizations in the primary and secondary mortgage markets. Evidence presented in the paper indicates that home purchase loan origination rates for black applicants—and, to a lesser degree, Hispanic applicants—appear to be significantly lower than those of other racial or ethnic groups. Similarly, the HMDA data reveal that home purchase mortgage origination rates in predominantly minority census tracts are significantly lower than those in predominantly white neighborhoods. The HMDA data also indicate a striking reliance of black borrowers on government‐backed forms of mortgage credit.

The paper further reveals that secondary market loan purchase distributions arrayed by borrower and neighborhood characteristics generally reflect those of home mortgage originations. The borrower and locational characteristics of home purchase loans acquired by the Government National Mortgage Association (GNMA) directly reflect that agency's legislated specialization in government‐backed loans, whereas the characteristics of loans acquired by Fannie Mae and Freddie Mac for the most part derive from the borrower and geographic composition of conventional home purchase loan originations. Findings of analyses of HMDA data raise concern regarding the access of minority and low‐income households and neighborhoods to mortgage finance. Those results also raise some question as to whether the federally chartered agencies in the secondary market are adequately promoting the availability of mortgage credit to low‐ and moderate‐income and minority households.  相似文献   
749.
750.
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