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971.
Although computers are universal in the classroom, nearly 20 million children in the United States do not have computers in their homes. Surprisingly, only a few previous studies explore the role of home computers in the educational process. Home computers might be very useful for completing school assignments, but they might also represent a distraction for teenagers. We use several identification strategies and panel data from the two main U.S. data sets that include recent information on computer ownership among children—the 2000–2003 Current Population Survey (CPS) Computer and Internet Use Supplements matched to the CPS basic monthly files and the National Longitudinal Survey of Youth 1997 (NLSY97)—to explore the causal relationship between computer ownership and high school graduation and other educational outcomes. Teenagers who have access to home computers are 6–8 percentage points more likely to graduate from high school than teenagers who do not have home computers after controlling for individual, parental, and family characteristics. We generally find evidence of positive relationships between home computers and educational outcomes using several identification strategies, including controlling for typically unobservable home environment and extracurricular activities in the NLSY97, fixed effects models, instrumental variables, and including future computer ownership and falsification tests. Home computers may increase high school graduation by reducing nonproductive activities, such as truancy and crime, among children in addition to making it easier to complete school assignments (JEL I2). 相似文献
972.
The asymptotic distribution of estimators generated by the methods of moments and maximum likelihood are considered. Simple formulae are provided which enable comparisons of asymptotic relative efficiency to be effected. 相似文献
973.
As assumed hypothetical consensus category corresponding to a case being classified provides a basis for assessment of reliability of judges. Equivalent judges are characterised by the joint probability distribution of the judge assignment and the consensus category. Estimates of the conditional probabilities of judge assignment given consensus category and of consensus category given judge assignments are indices of reliability. All parameters can be estimated if data include classifications of a number of cases by 3 or more judges. Restrictive assumptions are imposed to obtain models for data from classifications by two judges. Maximum likelihood estimation is discussed and illustrated by example for the 3 or more judges case. 相似文献
974.
The objective of the paper is to apply the statistical procedure of ridge regression to a multivariate model of criminal activity. The explanatory variables are of an economic, apprehension, and seasonal nature. The Time Shared Reactive On Line Laboratory (TROLL) computer package was used in estimating all regression coefficients and other pertinent statistics. The economic variables, which included per capita personal income, hours worked, and plant closing dummy variable, were found to be statistically related to criminal activity. In addition, police expenditures as well as the three seasonal dummy variables were statistically associated with the dependent variable. A comparison is made between the results obtained from the ordinary least squares procedure and the ridge regression approach. 相似文献
975.
L. H. Evers 《Australian Social Work》2013,66(3):11-20
Australian Marriage Guidance Councils are rarely considered avant garde. Yet contemporary emphasis on the importance of citizen participation in social service delivery programmes1 unexpectedly shows them in the vanguard of the new art of mobilizing participatory community services. For more than a quarter of a century now they have been operating as expert guides and counsellors in the difficult territory of marital therapy, mainly using staffs of part-time counsellors drawn from the general community. The magnitude of this feat of maintaining the participatory character of this community service in a potentially rich field for professional exploitation goes largely unacknowledged. It has been pointed out that the professional, “because of his status, commitment and knowledge”,2 is in most cases successful in converting citizen participation programmes into the service of his own professional interest. This has always been one of the most intractable problems of any participatory scheme. So far the Marriage Guidance Councils have stayed right on top of this problem. 相似文献
976.
Friends' influence on achievement‐related choices in female adolescents was investigated using the Thematic Apperception Test (H. Murray, 1943), in the context of self‐in‐relation theory (J. V. Jordon, A. G. Kaplan, J. B. Miller, I. P. Stiver, & J. L. Surrey, 1991). Two hypotheses were tested: (1) Achievement‐related stimuli will elicit stories with more unfavorable and conflicted outcomes than will affiliation stimuli; (2) Thematic representation of achievement will be more homogeneous in more highly cohesive peer groups. A multivariate analysis of variance with repeated measures yielded significant results for Hypothesis 1. Thematic analysis of stories supported Hypothesis 2, showing peer group influence on achievement strivings in female adolescents. 相似文献
977.
An inverse regression approach to analyzing quantal response assays with one quanritative independent- variable and any number of qualitative independent variables is presented. A general factorial model ror LQC- inverted relationship and methods of testing hypotheses estimating qulitative Interest are developed. This naper provides a modified method of analysis which is easier to apply than previously existing methods. 相似文献
978.
This article presents an empirical analysis of firms' order backlogs, inventories, production, and price adjustments to unanticipated demand shocks. The data are obtained from quarterly INSEE Business Survey Tests on firms' realizations, expectations, and appraisals of some various economic variables. The analysis is based on the formulation and the estimation of a recursive system of conditional log-linear probability models. 相似文献
979.
Routine implementation of the Bayesian paradigm requires an efficient approach to the calculation and display of posterior or predictive distributions for given likelihood and prior specifi- cations. In this paper we shall review some of the analytic and numerical approaches currently available, describing in detail a numerical integration strategy based on Gaussian quadrature, and an associated strategy for the reconstruction and display of distributions based on spline techniques. 相似文献
980.