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   26158篇
  免费   684篇
  国内免费   1篇
管理学   3804篇
民族学   105篇
人才学   1篇
人口学   2517篇
丛书文集   100篇
教育普及   2篇
理论方法论   2293篇
现状及发展   1篇
综合类   340篇
社会学   12419篇
统计学   5261篇
  2021年   150篇
  2020年   385篇
  2019年   515篇
  2018年   644篇
  2017年   862篇
  2016年   644篇
  2015年   476篇
  2014年   645篇
  2013年   4207篇
  2012年   857篇
  2011年   820篇
  2010年   607篇
  2009年   527篇
  2008年   575篇
  2007年   627篇
  2006年   597篇
  2005年   583篇
  2004年   532篇
  2003年   497篇
  2002年   562篇
  2001年   697篇
  2000年   697篇
  1999年   610篇
  1998年   464篇
  1997年   415篇
  1996年   426篇
  1995年   400篇
  1994年   374篇
  1993年   378篇
  1992年   458篇
  1991年   410篇
  1990年   387篇
  1989年   383篇
  1988年   367篇
  1987年   321篇
  1986年   323篇
  1985年   366篇
  1984年   366篇
  1983年   360篇
  1982年   305篇
  1981年   256篇
  1980年   239篇
  1979年   281篇
  1978年   251篇
  1977年   227篇
  1976年   197篇
  1975年   215篇
  1974年   169篇
  1973年   163篇
  1971年   134篇
排序方式: 共有10000条查询结果,搜索用时 375 毫秒
161.
162.
Extractive industries such as logging and mining are generally expected to bring significant economic benefits to rural regions, but a growing number of findings have now challenged that common expectation. Still, it is not clear whether the findings of less–than–desirable economic outcomes are isolated or representative. In this article, we assemble literally all of the relevant quantitative findings on mining that we have been able to identify in published and/or technical literature from the United States. In the interest of rigor, we limit the assessment to cases in which strictly nonmetropolitan mining regions are compared against other nonmetropolitan regions and/or against those regions’ own experiences over time. Overall, 301 findings meet the criteria for inclusion. Contrary to the long–established assumptions, but consistent with more recent critiques, roughly half of all published findings indicate negative economic outcomes in mining communities, with the remaining findings being split roughly evenly between favorable and neutral/indeterminate ones. Positive findings are more likely to be associated with incomes than with poverty or (especially) unemployment rates, and they are more likely to come from the western United States, where much of the mining involves relatively large, new coal strip mines. Over half of all positive findings come from the years prior to 1982. In virtually all other categories, the plurality or majority of findings have been negative. When the patterns of findings are subjected to one–sample means tests, the only way to produce a significantly positive outcome is by combining all neutral/indeterminate findings with the positive ones, while focusing exclusively on incomes; by contrast, in the case of poverty or unemployment rates—as well as for the overall body of findings—the results are consistently and significantly negative, whether the neutral/indeterminate findings are combined with negative ones or omitted from the equations altogether. Until or unless future studies produce dramatically different findings, there appears to be no scientific basis for accepting the widespread, “obvious” assumption that mining will lead to economic improvement.  相似文献   
163.
Proponents of hazardous and nuclear waste depositories label opponents to local siting of such facilities “NIMBYs” (Not In My Backyard). This study assesses the extent to which the NIMBY label and the strategies of industry proponents to reduce opposition function on a reasonable set of assumptions. Using survey data and multiple regression techniques, the levels of concern of residents living in the county selected as the site of a low level radioactive waste disposal facility (imminent threat condition) are compared with a statewide sample (hypothetical threat condition). Consistent with proponents' theoretical assumptions, the levels of concern are greater for respondents under conditions of imminent threat than of hypothetical threat. However, within the host county, levels of concern are lowest, albeit most polarized, in the community closest to the proposed site. A conflict theory approach enhances an understanding of these findings by suggesting that within the most proximate community levels of concern are lowest for citizens who stand to gain the most economic benefits from the facility but highest for those citizens who are least likely to derive tangible gains.  相似文献   
164.
This paper describes the theoretical foundations, empirical findings, and practical and philosophical implications of the Boston Area Diary Study (BADS), a study of the caring behavior of 44 participants over one calendar year. In particular, the paper presents an identification theory of care and discusses how it shaped the conceptualization, collection, and analysis of the data in a year-long diary study of daily voluntary assistance. The findings from the BADS (1) theoretically confirm the identification theory of care; (2) methodologically capture how individuals perceive and carry out caring behavior as a unity; and (3rpar; empirically document the existence of a moral citizenship in America that is substantially more vigorous than is implied by the usual indicators of civic and political citizenship.  相似文献   
165.
A powerful practical solution is by far the most desired output when making decisions under the realm of uncertainty on any safety-critical marine or offshore units and their systems. With data and information typically being obtained incrementally, adopting Bayesian network (BN) is shown to realistically deal with the random uncertainties while at the same time making risk assessments easier to build and to check. A well-matched methodology is proposed to formalize the reasoning in which the focal mechanism of inference processing relies on the sound Bayes's rule/theorem that permits the logic. Expanding one or more influencing nodal parameters with decision and utility node(s) also yields an influence diagram (ID). BN and ID feasibility is shown in a marine evacuation scenario and that of authorized vessels to floating, production, storage, and offloading collision, developed via a commercial computer tool. Sensitivity analysis and validation of the produced results are also presented.  相似文献   
166.
A log-linear modelling approach is proposed for dealing with polytomous, unordered exposure variables in case-control epidemiological studies with matched pairs. Hypotheses concerning epidemiological parameters are shown to be expressable in terms of log-linear models for the expected frequencies of the case-by-control square concordance table representation of the matched data; relevant maximum likelihood estimates and goodness-of-fit statistics are presented. Possible extensions to account for ordered categorical risk factors and multiple controls are illustrated, and comparisons with previous work are discussed. Finally, the possibility of implementing the proposed method with GLIM is illustrated within the context of a data set already analyzed by other authors.  相似文献   
167.
This paper suggests a direction for the exploration of the causes of family violence. Explanatory models of family violence were considered in this regard, with the recommendation that a multi-determined model should be considered to ensure the most accurate explanation. We suggest that family violence will be best understood and prevented or alleviated, if a model is used that considers the interaction of structural violence and the personality features of all the family members.  相似文献   
168.
The tutorial is concerned with two types of test for the general lack of fit of a linear regression model, as found in the Minitab software package, and which do not require replicated observations. They aim to identify non-specified curvature and interaction in predictors, by comparing fits over the predictor region divided into two parts. Minitab's regression subcommand XLOF which gives the tests is only briefly documented in the manual and, unlike virtually all other statistical procedures in the software, it is not standard and cannot be readily found in textbooks. The two types of test are described here; they concern the predictors one-at-a-time and the predictors all-at-once. An example of their use is given. A suite of macros is available which reproduces the results of the XLOF tests in much more detail than is given by the XLOF subcommand.  相似文献   
169.
Using data from the 1979–1980 National Survey of Black Americans (NSBA), this study investigates the relationships between religious involvement and two sets of racial orientations: identification , or feelings of closeness and commonality of interests among blacks, and separatism , or support for cultural and institutional distance from whites. Both public religious participation and private religious devotion are strong positive predictors of racial identification, net of the effects of sociodemographic factors. However, the positive effects of devotion on identification are diminished sharply among blacks over 60 years of age. In addition, members of tradition black denominations (i.e., Baptists and Methodists) express substantially stronger black identity than do their unaffiliated counterparts. In contrast to models of racial identification, religious involvement bears little consistent relationship to separatism. Relatively strong separatist sentiment is found among (1) frequent churchgoers ages 30–59 and (2) adherents of nontraditional religions (e.g., Muslims). In general, these results cast doubt on the arguments of some critics of the black church, who claim that religion undermines collective identification. Mainstream black religious culture appears to encourage inclusive, but not exclusive, racial solidarity.  相似文献   
170.
This paper presents an algorithm for the construction of optimal or near optimal change-over designs for arbitrary numbers of treatments, periods and units. Previous research on optimality has been either theoretical or has resulted in limited tabulations of small optimal designs. The algorithm consists of a number of steps:first find an optimal direct treatment effects design, ignoring residual effects, and then optimise this class of designs with respect to residual effects. Poor designs are avoided by judicious application of the (M, S)-optimality criterion, and modifications of it, to appropriate matrices. The performance of the algorithm is illustrated by examples.  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