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   13833篇
  免费   220篇
  国内免费   1篇
管理学   1943篇
民族学   60篇
人才学   2篇
人口学   1250篇
丛书文集   69篇
理论方法论   1374篇
综合类   182篇
社会学   6539篇
统计学   2635篇
  2020年   200篇
  2019年   272篇
  2018年   258篇
  2017年   389篇
  2016年   317篇
  2015年   254篇
  2014年   315篇
  2013年   2443篇
  2012年   413篇
  2011年   354篇
  2010年   314篇
  2009年   305篇
  2008年   385篇
  2007年   387篇
  2006年   336篇
  2005年   352篇
  2004年   348篇
  2003年   296篇
  2002年   337篇
  2001年   325篇
  2000年   275篇
  1999年   272篇
  1998年   241篇
  1997年   227篇
  1996年   212篇
  1995年   194篇
  1994年   173篇
  1993年   222篇
  1992年   210篇
  1991年   203篇
  1990年   192篇
  1989年   170篇
  1988年   175篇
  1987年   163篇
  1986年   148篇
  1985年   152篇
  1984年   171篇
  1983年   158篇
  1982年   152篇
  1981年   114篇
  1980年   140篇
  1979年   149篇
  1978年   118篇
  1977年   132篇
  1976年   117篇
  1975年   128篇
  1974年   106篇
  1973年   85篇
  1972年   82篇
  1971年   75篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
411.
For a connected graph \(G = \left( V,E\right) \), a set \(S\subseteq E(G)\) is called a total edge-to-vertex monophonic set of a connected graph G if the subgraph induced by S has no isolated edges. The total edge-to-vertex monophonic number \(m_{tev}(G)\) of G is the minimum cardinality of its total edge-to-vertex monophonic set of G. The total edge-to-vertex monophonic number of certain classes of graphs is determined and some of its general properties are studied. Connected graphs of size \(q \ge 3 \) with total edge-to-vertex monophonic number q is characterized. It is shown that for positive integers \(r_{m},d_{m}\) and \(l\ge 4\) with \(r_{m}< d_{m} \le 2 r_{m}\), there exists a connected graph G with \(\textit{rad}_ {m} G = r_{m}\), \(\textit{diam}_ {m} G = d_{m}\) and \(m_{tev}(G) = l\) and also shown that for every integers a and b with \(2 \le a \le b\), there exists a connected graph G such that \( m_{ev}\left( G\right) = b\) and \(m_{tev}(G) = a + b\). A forcing subset for S of minimum cardinality is a minimum forcing subset of S. The forcing total edge-to-vertex monophonic number of S, denoted by \(f_{tev}(S)\) is the cardinality of a minimum forcing subset of S. The forcing total edge-to-vertex monophonic number of G, denoted by \(f_{tev}(G) = \textit{min}\{f_{tev}(S)\}\), where the minimum is taken over all total edge-to-vertex monophonic set S in G. The forcing total edge-to-vertex monophonic number of certain classes of graphs are determined and some of its general properties are studied. It is shown that for every integers a and b with \(0 \le a \le b\) and \(b \ge 2\), there exists a connected graph G such that \(f_{tev}(G) = a\) and \( m _{tev}(G) = b\), where \( f _{tev}(G)\) is the forcing total edge-to-vertex monophonic number of G.  相似文献   
412.
International coopetition has rarely been studied in relation to innovation. Further exploration of effects of international coopetition, i.e. the pursuit of simultaneous cooperation and competition, on a firm’s innovation performance is especially important as such a relationship is challenging with a high propensity to fail. This observation formed the point of departure for this study, which aims to increase the understanding of the effects of international coopetition on firm innovativeness and how these effects are conditioned on the magnitude of the organizational adjustments a firm introduces. We use an unbalanced panel of 9839 firms that participated in four waves of the Swedish Community Innovation Survey between 2008 and 2014 as our empirical base. We illustrate that firms that cooperate with competitors internationally are more likely to exhibit higher propensity to introduce radical innovations, yet this effect is conditioned upon the magnitude of organizational adjustments. Overall, our study contributes to the understanding of the implications of international coopetition and what a firm needs to benefit from it.  相似文献   
413.
In this article, we examine birth cohort differences in parents’ provision of monetary help to adult children with particular focus on the extent to which cohort differences in family structure and the transition to adulthood influence these changes. Using data from the Health and Retirement Study from 1994 to 2010, we compare financial help to children of three respondent cohorts as the parents in these birth cohorts from ages 53–58 to 57–62. We find that transfers to children have increased among more recent cohorts. Two trends—declining family size and children’s delay in marriage—account for part of the increase across cohorts. However, other trends, such as the increase in the number of stepchildren and increasing child’s income level, tend to decrease the observed cohort trend.  相似文献   
414.
Over the past five years the Artificial Intelligence Center at SRI has been developing a new technology to address the problem of automated information management within real- world contexts. The result of this work is a body of techniques for automated reasoning from evidence that we call evidential reasoning. The techniques are based upon the mathematics of belief functions developed by Dempster and Shafer and have been successfully applied to a variety of problems including computer vision, multisensor integration, and intelligence analysis.

We have developed both a formal basis and a framework for implementating automated reasoning systems based upon these techniques. Both the formal and practical approach can be divided into four parts: (1) specifying a set of distinct propositional spaces, (2) specifying the interrelationships among these spaces, (3) representing bodies of evidence as belief distributions, and (4) establishing paths of the bodies for evidence to move through these spaces by means of evidential operations, eventually converging on spaces where the target questions can be answered. These steps specify a means for arguing from multiple bodies of evidence toward a particular (probabilistic) conclusion. Argument construction is the process by which such evidential analyses are constructed and is the analogue of constructing proof trees in a logical context.

This technology features the ability to reason from uncertain, incomplete, and occasionally inaccurate information based upon seven evidential operations: fusion, discounting, translation, projection, summarization, interpretation, and gisting. These operation are theoretically sound but have intuitive appeal as well.

In implementing this formal approach, we have found that evidential arguments can be represented as graphs. To support the construction, modification, and interrogation of evidential arguments, we have developed Gister. Gister provides an interactive, menu-driven, graphical interface that allows these graphical structures to be easily manipulated.

Our goal is to provide effective automated aids to domain experts for argument construction. Gister represents our first attempt at such an aid.  相似文献   

415.
埃德加·莫兰的复杂性思想主体包括三大理论:建立在有序性与无序性统一基础上的自组织理论、建立在整体与部分相互决定基础上的多样性理论以及建立在主客体相整合基础上的自我反思理论.莫兰的复杂性思想与"简单范式"针锋相对,自然构成了时以"简单范式"为基础的人类学的批判.本文以人类学研究的某些方面,如研究主体、文化的整体性、观察角度、价值取向、工作思路、研究态度以及研究角色等为例,进行了评析.  相似文献   
416.
417.
We examined consistency in self-reports of age at first vaginal sex among 9,399 male and female respondents who participated in Waves III and IV (separated by approximately seven years) of the National Longitudinal Study of Adolescent Health (Add Health). Respondents were coded as consistent if they reported an age at first vaginal intercourse at Wave IV that was within one year of the age they reported at Wave III. Sociodemographic, behavioral, and cognitive predictors of consistency were examined using bivariate and multivariate logistic regression. Overall, 85.43% of respondents were able to provide consistent reports. Among both males and females, consistency was associated with age, years since first vaginal intercourse, race/ethnicity, and lifetime number of other-sex partners in final multivariate models. Respondents who were older and had more recently had their first sexual experience were more likely to be consistent. For females only, those who reported a history of nonparental, physically forced sex were less likely to be consistent. Most young adults consistently report age at first vaginal intercourse, supporting the credibility of retrospective self-reports about salient sexual events such as timing of first vaginal intercourse.  相似文献   
418.
Prior to the Taxpayer Relief Act of 1997 (TRA97), the capital gain from the sale of a home was taxed differently for those over and under the age of 55. TRA97 eliminated this differential treatment. Using a difference‐in‐difference approach, we find that home sellers slightly under the age of 55 were 6.2% more likely to move for a less expensive house to maintain, 6.6% less likely to move for a larger place, and 5.2% more likely to reside in a condominium after TRA97's enactment, relative to those slightly over 55. (JEL H24, R21)  相似文献   
419.
420.
Quantitative research has resulted in inconsistent evidence for the existence of a sexual double standard, leading Crawford and Popp ( 2003 ) to issue a call for methodological innovation. The implicit association test (IAT; Greenwald, McGhee, & Schwartz, 1998 ) is a measure that may provide a means to examine the double standard without the contamination of the demand characteristics and social desirability biases that plague self-report research (Marks & Fraley, 2005 ). The purpose of this study was to examine the factors influencing explicit and implicit double standards, and to examine the relationship between these explicit and implicit double standards, and levels of socially desirable responding. One hundred and three university students completed a sexual double standard IAT, an explicit measure of the double standard, and measures of socially desirable responding. Hierarchical regression analysis indicated that levels of socially desirable responding were not related to implicit or explicit double standards. Men endorsed a stronger explicit traditional double standard than women, whereas for implicit sexual standards, men demonstrated a relatively gender-neutral evaluation and women demonstrated a strong reverse double standard. These results suggest the existence of a complex double standard, and indicate that more research of sexual attitudes should include implicit measures.  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