首页 | 官方网站   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   7802篇
  免费   202篇
社会科学   8004篇
  2021年   52篇
  2020年   90篇
  2019年   129篇
  2018年   167篇
  2017年   244篇
  2016年   199篇
  2015年   149篇
  2014年   175篇
  2013年   1359篇
  2012年   297篇
  2011年   217篇
  2010年   175篇
  2009年   158篇
  2008年   192篇
  2007年   180篇
  2006年   138篇
  2005年   197篇
  2004年   174篇
  2003年   214篇
  2002年   231篇
  2001年   217篇
  2000年   192篇
  1999年   185篇
  1998年   143篇
  1997年   112篇
  1996年   127篇
  1995年   105篇
  1994年   97篇
  1993年   105篇
  1992年   125篇
  1991年   115篇
  1990年   112篇
  1989年   102篇
  1988年   110篇
  1987年   110篇
  1986年   103篇
  1985年   119篇
  1984年   94篇
  1983年   103篇
  1982年   70篇
  1981年   74篇
  1980年   69篇
  1979年   72篇
  1978年   73篇
  1977年   49篇
  1976年   42篇
  1975年   55篇
  1974年   47篇
  1973年   39篇
  1972年   39篇
排序方式: 共有8004条查询结果,搜索用时 421 毫秒
71.
Abstract The objective of this study is to examine female labor force participation and its determinants in rural and urban China. The sociological literature has demonstrated that participation tends to increase in urban and industrialized places where women have higher levels of education and fewer children, where more workers are engaged in service pursuits, and where family structure is less traditional. With the use of data on counties and cities (N = 2,377) from the I-percent sample of the 1982 census of the People's Republic of China, it was found that female labor force participation is likely to rise in areas with increased agricultural employment, educational levels, proportion of female-headed households, and higher male-to-female sex ratios. Both the size of the service sector and the fertility rate had negligible effects on female labor force participation. Although, on average, rural places have slightly higher levels of female labor force participation, when other variables are controlled, urban places have a higher rate of female participation. In addition, the findings suggest that market factors (i.e., education) are more likely to determine the rate of female labor force participation in urban areas; whereas demographic and social factors (i.e., sex ratio and household structure) play a more important role in explaining the female labor force participation in rural counties.  相似文献   
72.
73.
This paper develops a likelihood‐based method for fitting additive models in the presence of measurement error. It formulates the additive model using the linear mixed model representation of penalized splines. In the presence of a structural measurement error model, the resulting likelihood involves intractable integrals, and a Monte Carlo expectation maximization strategy is developed for obtaining estimates. The method's performance is illustrated with a simulation study.  相似文献   
74.
Abstract Rural women have difficulty finding good jobs. Ownership of small businesses offers an alternative but the sales and income of women-owned firms are significantly lower than those of men-owned firms. Compared with men, women owners are more likely to operate smaller and newer businesses; however, these differences do not completely account for the gap in gross sales between men- and women-owned businesses. The strongest influences on business success are firm size, corporate status, and industrial sector. Though significant, the owner's gender is less important than these organizational characteristics. The factors influencing success of small businesses generally are the same for men- and women-owned businesses. More research on business networks and the start-up phase of small businesses is necessary for a better understanding of the sources of gender differences in success.  相似文献   
75.
Summary This paper solves some D-optimal design problems for certain Generalized Linear Models where the mean depends on two parameters and two explanatory variables. In all of the cases considered the support point of the optimal designs are found to be independent of the unknown parameters. While in some cases the optimal design measures are given by two points with equal weights, in others the support is given by three point with weights depending on the unknown parameters, hence the designs are locally optimal in general. Empirical results on the efficiency of the locally optimal designs are also given. Some of the designs found can also be used for planning D-optimal experiments for the normal linear model, where the mean must be positive. This research was carried out in part at University College, London as an M.Sc. project. Thanks are due to Prof. I. Ford (University of Glasgow) and Prof. A. Giovagnoli (University of Perugia) for their valuable suggestions and critical observations.  相似文献   
76.
Much recent cultural criticism points out the ways in which “writing about ‘the Other’” perpetuates, justifies and participates in the creation of “real-life” relations of domination and oppression between the “authors” (located in the center(s) of power and knowledge) and their “subject matters.” This paper takes a different approach and explores theliberating potentials of “writing about ‘the Other.’” Completed in the spring of 1991, in the wake of changes in Eastern Europe from the fall of 1989, this paper gives a loose mapping of the nascent Eastern European cultural constellations, as well as an elaboration of the position of a “native” intellectual, in order to circuitously come to the point from which it can articulate the ways in which “Western” writing about “Eastern Europe” can create liberating interventions in the struggles going on in Eastern Europe.  相似文献   
77.
该文从中国人口快速增长、经济建设加快、用水量逐年增大 ,加上气候变暖、少雨干旱将持续到 2 0 15年 ,我国北方水生态环境日趋恶化现状 ,说明在丰水区筑坝截流、调丰补歉势在必行 ,完全符合生态经济学发展原则和国际水法  相似文献   
78.
Formulae are provided that define the ‘bend points’, the beginning and end of the essentially linear dose–response region, for the four‐parameter logistic model. The formulae are expressed in both response and dose units. The derivation of the formulae is shown in order to illustrate the general nature of the methodology. Examples are given that describe how the formulae may be used while planning and conducting bioassays. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
79.
In this article, we describe a straightforward method for solving the probability of at least one malignant cell by time t, and the associated hazard function, in the general (i.e., nonhomogeneous) two-stage Moolgavkar-Venzon-Knudson (MVK) model of cancer. The method consists of solving four coupled ordinary differential equations derived from the Kolmogorov backward equations for this process. The relationship of this method to previously proposed solutions is discussed.  相似文献   
80.
Summary The evaluation of the performance of seasonal adjustment procedures is an issue of practical importance in view of the unobservable nature of the components. Looking at just one indicator when judging the overall quality of a procedure may be misleading, even though this is common practice when many series are involved. The main purpose of this paper is to compare the information content of different synthetic indicators with reference to the X-11-ARIMA procedure. Sixty-six different types of monthly seasonal series are generated and the seasonal component then extracted by carrying out X-11-ARIMA with standard options. The correlation between the pseudo-true error for each series and various synthetic indicators allows us to compare the latter's reliability, under both the hypotheses of minimum and maximum variance of the pseudo-true seasonal component. We show that the overall quality indexQ-the indicator most commonly adopted by users of the X-11-ARIMA-is always outperformed by the simpler diagnostics based on the stability of the estimates. In particular, the “sliding-spans” indicator, proposed by Findley et al. (1990) and included in the diagnostics of the new X-12 procedure, shows a much stronger correlation with the pseudo-true error in the seasonal adjustment. We also show that the total forecasting errors in the one-year-ahead extrapolation of the seasonal component have a good informative power and perform almost as well as the “sliding-spans” indicator.  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-23

京公网安备 11010802026262号