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   19216篇
  免费   356篇
管理学   2212篇
民族学   105篇
人才学   6篇
人口学   1794篇
丛书文集   110篇
教育普及   2篇
理论方法论   1805篇
现状及发展   1篇
综合类   244篇
社会学   9693篇
统计学   3600篇
  2023年   109篇
  2022年   81篇
  2021年   101篇
  2020年   305篇
  2019年   490篇
  2018年   499篇
  2017年   693篇
  2016年   487篇
  2015年   371篇
  2014年   461篇
  2013年   3230篇
  2012年   683篇
  2011年   602篇
  2010年   482篇
  2009年   456篇
  2008年   524篇
  2007年   523篇
  2006年   490篇
  2005年   447篇
  2004年   440篇
  2003年   405篇
  2002年   412篇
  2001年   476篇
  2000年   393篇
  1999年   387篇
  1998年   314篇
  1997年   284篇
  1996年   289篇
  1995年   277篇
  1994年   261篇
  1993年   254篇
  1992年   289篇
  1991年   289篇
  1990年   262篇
  1989年   260篇
  1988年   244篇
  1987年   229篇
  1986年   219篇
  1985年   246篇
  1984年   236篇
  1983年   234篇
  1982年   177篇
  1981年   156篇
  1980年   170篇
  1979年   170篇
  1978年   141篇
  1977年   140篇
  1976年   123篇
  1975年   115篇
  1974年   96篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
131.
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   
132.
"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   
133.
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   
134.
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   
135.
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   
136.
Bangladesh has a population of 115 million people, and the economic growth rate of 3.7% during the 1980s was undermined by rapid population growth. The annual population growth rate was 3% in the 1960s and early 1970s, 2.5% between 1981-91 decreasing to 2.3% in 1991. The average of number of children is 4.6/woman compared with 7 in the 1960s. Infant mortality dropped from 150/1000 births in 1976 to 118/1000 in 1991. Life expectancy rose from 47 to 54 years. The 1991 Contraceptive Prevalence Survey showed that 39.9% of married women under 50 use contraceptives in 1991 vs. 18.6% in 1981. The use of modern methods increased from 10.9% in 1981 to 31.2% in 1991, while traditional methods rose from 7.7% to 8.7%. Sterilization was most prevalent in 1981. 29,000 female family planning (FP) workers were aggressively engaged in dispensing FP services in 1990. The Social Marketing Company sells pills, condoms, and oral rehydration salts through 130,000 retail outlets. The 1989 Contraceptive Prevalence Survey showed that 40% of pill and condom users obtained them from this network, and 95.4% of women knew about 4 methods of contraception. In 1990 there were 120 private organizations providing contraceptive services. Some of the components of the government FP program include field worker distribution door-to-door of injectable contraceptives (50% injectable usage rate in the Matlab project); recordkeeping activities; a satellite clinic network with access to contraceptive services; and decentralization through the Upazila (subdistrict) approach. The logistics system of FP has improved the warehousing, transportation, and management information system. Foreign aid (mainly USAID) financing of contraceptives helped avert 14.4 million births between 1974-90. The increase of contraceptive prevalence to 50% by 1997 would avert another 21.9 million births during 1991-96 (replacement fertility requires 70% prevalence.  相似文献   
137.
In this paper the timing of maternity is estimated by a hazard model. The novel aspect of this paper is that it is shown that wages and total household labor income have a significant effect on the timing of maternity. Both the wage rate of the woman and the wage rate of the husband have a negative effect on the timing of maternity. Total household labor income increases the probability of having a child at an earlier age. Calculated elasticities show that the timing of maternity is relatively elastic with respect to wage rates. However, the elasticities of the decision whether or not to have children altogether are much smaller. Women working in the labor market delay the timing of maternity compared to non-participating women. Attending school has the same effect. Until the age of 28 the maternity hazard increases with age, after that it decreases.We benefited from comments on previous drafts by Siv Gustafsson, Joop Hartog, Peter Kee, Herriette Maassen van den Brink, Eddie Mekkelholt, Joop Odink, Hessel Oosterbeek, Hans van Ophem, Gusta Renes, Andre Voskamp, two anonymous referees, and the Managing Editor of this Journal. This paper is a revised version of a paper presented at the third annual meeting of the European Society for Population Economics, Paris, June 1989. The usual disclaimer applies.  相似文献   
138.
139.
140.
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