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   96534篇
  免费   1982篇
  国内免费   3篇
管理学   12940篇
民族学   580篇
人才学   25篇
人口学   7787篇
丛书文集   539篇
教育普及   3篇
理论方法论   9668篇
现状及发展   1篇
综合类   2267篇
社会学   45543篇
统计学   19166篇
  2023年   513篇
  2021年   580篇
  2020年   1535篇
  2019年   2224篇
  2018年   2232篇
  2017年   3308篇
  2016年   2502篇
  2015年   2056篇
  2014年   2655篇
  2013年   18911篇
  2012年   2717篇
  2011年   2548篇
  2010年   2142篇
  2009年   2276篇
  2008年   2279篇
  2007年   2095篇
  2006年   2259篇
  2005年   2430篇
  2004年   2305篇
  2003年   2022篇
  2002年   2114篇
  2001年   2181篇
  2000年   1949篇
  1999年   1829篇
  1998年   1582篇
  1997年   1437篇
  1996年   1399篇
  1995年   1420篇
  1994年   1374篇
  1993年   1352篇
  1992年   1406篇
  1991年   1337篇
  1990年   1306篇
  1989年   1133篇
  1988年   1208篇
  1987年   1080篇
  1986年   994篇
  1985年   1165篇
  1984年   1210篇
  1983年   1083篇
  1982年   990篇
  1981年   898篇
  1980年   850篇
  1979年   930篇
  1978年   816篇
  1977年   749篇
  1976年   688篇
  1975年   666篇
  1974年   553篇
  1973年   468篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
901.
This paper studies two models of rational behavior under uncertainty whose predictions are invariant under ordinal transformations of utility. The quantile utility model assumes that the agent maximizes some quantile of the distribution of utility. The utility mass model assumes maximization of the probability of obtaining an outcome whose utility is higher than some fixed critical value. Both models satisfy weak stochastic dominance. Lexicographic refinements satisfy strong dominance.The study of these utility models suggests a significant generalization of traditional ideas of riskiness and risk preference. We define one action to be riskier than another if the utility distribution of the latter crosses that of the former from below. The single crossing property is equivalent to a minmax spread of a random variable. With relative risk defined by the single crossing criterion, the risk preference of a quantile utility maximizer increases with the utility distribution quantile that he maximizes. The risk preference of a utility mass maximizer increases with his critical utility value.  相似文献   
902.
903.
This paper examines the effects of introducing a variable dependency ratio in Dasgupta's (1969) model. We consider a case in which the probability of dying as well as the rate of participation in the labor force change with age. It is shown that the inclusion of those realistic demographic features slows down the optimal rate of population growth and increases the rate of consumption. In spite of the reduction in the rate of population growth, this rate can still be positive. The sensitivity of the solutions to changes in the demographic parameters of the model is examined.  相似文献   
904.
"This article reports findings that have emerged from an effort made at statistically measuring the effects of immigration on the earnings of U.S.-born youth. The presence of immigrants arriving before 1965 has a positive impact on youth earnings. Recently arrived immigrants impact negatively, however. These results are consistent with recent findings that the skill level of immigrants arriving within the last two decades is lower relative to that of immigrants arriving earlier. The results also show that the negative effects diminish as the youth ages, reflecting skill acquisition and job mobility of the young worker into jobs less vulnerable to competition from immigrant workers."  相似文献   
905.
This study proposes and demonstrates an analytic paradigm based upon a substantive categorization of a set of inmigration correlates. It exemplifies the notion of categorizing, analyzing according to the categorization, and subsequently discussing the phenomenon in more depth. The paradigm has 2 steps: 1) the variables are categorized according to the cells resulting from the intersection of a preferably small number of nominal dimensions and 2) the data are analyzed, directly anchored in the prior categorization. The data used is Israel's 1983 census macro-data gathered from the Central Bureau of Statistics for the Israeli towns with populations of at least 5000. The authors defined 6 variables as push variables and 4 as pull variables. Results of the regression employing push variables show that 4 variables accounting for 72% of inmigration were found to significantly predict inmigration: 1) unemployment, 2) percentage of Asians-Africans, 3) town size, and 4) religiosity. Within the pull classification, the regression analysis reveals that 2 of the 4 variables explain 31% of the inmigration variance: 1) educational level (26%) and 2) income (5%). The 1st regression analysis on the 2nd dimension shows that the percentage of Asian-African origin and town population size account for 32% of the immigration variance. In the 2nd regression analysis, unemployment explains 48% of the inmigration variance and educational level explains 8%. In the 3rd regression, only home crowding explains a significant amount of the immigration variance (19%). Results of a multiple regression analysis show that unemployment level, percentage of Asian-Africans, population size, and level of religiosity account for 72% of the inmigration variance. Thus, the characteristics of a town inmigrating (push variables) are demographic, economic, and social. However, the attractive features of a town are only economic. Among all economic factors, unemployment is primary. In addition, not only are both percentage of Asians-Africans and population size significantly deflective of inmigration, but each also plays a separate and independent role.  相似文献   
906.
This paper extends the author's recent work on dynamically consistent consequentialist social norms for an unrestricted domain of decision trees with risk to trees in which the population is a variable consequence — i.e., endogenous. Given a form of ethical liberalism and ethical irrelevance of distant ancestors, classical utilitarianism is implied (provided also that a weak continuity condition is met). The repugnant conclusion that having many poor people may be desirable can be avoided by denying that individuals' interests extend to the circumstances of their birth. But it is better avoided by recognizing that potential parents have legitimate interests concerning the sizes of their families.That action is best, which procures the greatest happiness for the greatest numbers. Francis Hutchison (1725).An abiding interest in concepts of optimality for the choice of population has been stimulated by frequent discussions with Partha Dasgupta. This paper was presented at the seminar on Distributive Justice and Inequality at the Wissenschaftskolleg zu Berlin, May 1986. I am grateful to the audience for their helpful comments, especially Maurice Salles and Patrick Suppes, and especially to John Weymark for carefully reading and suggesting distinct improvements to the earlier version.  相似文献   
907.
Excuse-making is defined, and the issues of deception and verbal/nonverbal presentations are discussed in regard to the excuse process. Subsequently, the deception and verbal/nonverbal issues are described in greater detail in the context of whether the excuse occurs temporally after a negative outcome (retrospective), before a negative outcome (anticipatory), or as part of the characterological makeup of the person (incorporated). Going from retrospective to anticipatory to incorporated excuses, it is concluded that the role of nonverbal factors increases. Likewise, in the progression from making to being the excuse, it is argued that self- and other-deception also become more pervasive.  相似文献   
908.
It was tested whether professional actors would be able to communicate emotional meaning via facial expression when this is presented to judges without context information. Forty takes were selected from movies, depicting a female or a male actor in close-up showing facial expression. These close-ups were selected by two expert judges, who knew the complete movie and had to agree on the emotion expressed or expected to be expressed by the female or male actor in the respective take. Five takes each were selected to represent the basic emotions of joy, sadness, fear, and anger. Twenty takes each were selected showing female and male actors. These 40 takes (edited in random order onto video tape) were presented to 90 judges (about half female and half male; about half younger pupils and about half older ones), whose task it was to judge the emotion(s) expressed on nine 5-point-emotion scales. Results indicated that female actors are somewhat better (though not statistically significant) in communicating emotion via facial expression without context than male actors are. Furthermore, significant interactions between portrayed emotion and gender of actors were found: While recognition rate for joy is very high and identical for both genders, female actors seem to be superior in communicating fear and sadness via facial expression, while male actors are more successful in communicating anger. A display rule approach seems to be appropriate for the interpretation of these results, indicating that gender-specific attempts to control/inhibit certain emotions do not only exist in real life, but also in movies.The research reported here was supported by a grant of the Deutsche Forschungsgemeinschaft (WA 519/2-2). I thank Uwe Balser and Tina Mertesacker for their help in selecting the stimuli, preparing the judgment tapes, recruiting subjects and conducting the study.  相似文献   
909.
This article discusses the role of migration in relieving population pressures, thus making continuing development possible, using small nations in the Caribbean and the South Pacific as examples. The Caribbean islands and many Pacific islands have used out-migration to ease population pressures in this century. Surplus labor has been emerging in various Caribbean nations, independent of the international marketing problems of plantation agriculture. Rural populations alienated from plantations have had to make do on questionable and/or remote land. Population surpluses appear to originate in rural areas, but little evidence exists to suggest that those surpluses are the basis for the emigration patterns of the Caribbean islands. Emigration does not solve population problems because when ambitious, skilled workers leave their country, their actions have little to do with the existence of domestic surplus labor and their leaving may do little to facilitate domestic labor absorption. Thus, if mini-states wish to sustain their hopes of economic expansion, they must find the means to employ their surplus labor. Since mainly skilled migrants leave, their going may actually slow development and retard opportunities for labor absorption. Population movements internal to the Caribbean region may further complicate surplus labor and/or population problems. If protective entry requirements impede normal inter-island relations, they may interfere with developmental processes. In general, migration is not a feasible strategy for population control for small island nations. While temporary migration has a more positive impact than other forms of migration, problems do exist. For example, temporary migration 1) can impose significant economic costs on the source-country, and 2) may result in the source country being unable to capitalize on its initial investment in training and education of temporary migrants. In conclusion, import substitution through cooperation between small island nations, production for export where feasible, and more attention to more sophisticated international service linkages hold a better prospect for material progress than relying on the export of surplus populations.  相似文献   
910.
A face-to-face survey conducted in 1984 with a sample of 1491residents of the Detroit metropolitan area (including an oversampleof older adults) and a reinterview of a random subset of theserespondents by telephone were used to compare the two modesof data collection across two age levels. Except for a tendencytoward a disproportionately large number of DK answers and adisproportionately large amount of interviewer assistance onthe telephone, respondents 60 years of age and older did notexhibit larger mode differences than did respondents under 60.For both age groups, response distributions were rather similar,suggesting little effect of mode. Likewise, response style differedlittle by mode, while a higher proportion of missing data (i.e.,"I don't know" answers) was given on the telephone. The responserate for the telephone reinterview was 90%, somewhat lower forolder than younger persons. The findings support the feasibilityof using the telephone for reinterviewing older adults.  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