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231.
W.G. Runciman 《The Sociological review》2009,57(2):357-359
232.
Frank W. Finger 《Journal of sex research》2013,50(4):304-317
Abstract Replication of an earlier survey, using the same questionnaire in the same college course, reveals an increase in proportion of male students with premarital heterosexual experience, from 45 per cent in 1943–44 to 61.8 per cent in 1967–68 and 74.9 per cent in 1969–73. While the mean number of episodes is also greatly increased, the tendency is toward reducing the number of partners. Since the proportion condoning premarital intercourse has risen to over 90 per cent, still further increments in activity may be anticipated. The number reporting homosexual behavior (most often limited to the pre‐ and early‐adolescent years) has declined from 27 per cent to 13.7 per cent, but the amount of activity during the college years has increased. Students having experienced a particular sexual activity impute that activity to a higher proportion of the general population than do the inexperienced. 相似文献
233.
It appears to be common practice with ridge regression to obtain a decomposition of the total sum of squares, and assign degrees of freedom, according to established least squares theory. This discussion notes the obvious fallacies of such an approach, and introduces a decomposition based on orthogonality, and degrees of freedom based on expected mean squares, for non-stochastic k. 相似文献
234.
Using existing data from the 1999 Harvard School of Public Health College Alcohol Study, this study analyzes the social predictors of unwanted sexual advances experienced by college women and where this type of victimization occurs. Routine activities theory informed the analysis. While attendance and increased alcohol consumption at bars have a significant effect on experiences of unwanted sexual advances, attendance at parties, attendance at drink promotions, and participation in drinking games does not. Furthermore, while less satisfaction with education, having more sexual partners and friends that binge drink, and having more alcohol-related problems increase the likelihood of experiencing unwanted sexual advances, so does drinking less in general, having higher educated parents, and having a higher grade point average. These findings show that the predictors of unwanted sexual advances may differ somewhat from those that predict more serious forms of sexual victimization. Implications for future research and policy are discussed. 相似文献
235.
The performance of the balanced half-sample, jackknife and linearization methods for estimating the variance of the combined ratio estimate is studied by means of a computer simulation using artificially generated non-normally distributed populations. The results of this investigation demonstrate that the variance estimates for the combined ratio estimate may be highly biased and unstable when the underlying distributions are non-normal. This is particularly true when the number of observations available from each stratum is small. The jack- 相似文献
236.
Robert?Joseph?TaylorEmail authorView authors OrcID profile Dawne?M.?Mouzon Ann?W.?Nguyen Linda?M.?Chatters 《Race and social problems》2016,8(4):326-339
This study examined reciprocal support networks involving extended family, friends and church members among African Americans. Our analysis examined specific patterns of reciprocal support (i.e., received only, gave only, both gave and received, neither gave or received), as well as network characteristics (i.e., contact and subjective closeness) as correlates of reciprocal support. The analysis is based on the African American subsample of the National Survey of American Life. Overall, our findings indicate that African Americans are very involved in reciprocal support networks with their extended family, friends and church members. Respondents were most extensively involved in reciprocal supports with extended family members, followed closely by friends and church networks. Network characteristics (i.e., contact and subjective closeness) were significantly and consistently associated with involvement with reciprocal support exchanges for all three networks. These and other findings are discussed in detail. This study complements previous work on the complementary roles of family, friend and congregational support networks, as well as studies of racial differences in informal support networks. 相似文献
237.
Roger W. Schmenner 《Production and Operations Management》2015,24(2):341-350
This study names a pantheon of entrepreneurs and managers who have introduced a range of far‐reaching productivity innovations throughout modern history. The thread tying together all of the innovations, in whatever sector of the economy one examines, is the theory of swift, even flow. The study argues why swift, even flow explains the power and long‐lasting nature of these innovations and why other factors thought by some to affect productivity fall short. 相似文献
238.
AbstractThis research develops a model of relationships among components of Total-JIT, including JIT-information, JIT-manufacturing, JIT-purchasing, and JIT-selling, to establish an implementation hierarchy based on relative importance. The data collected relates to the relationships among JIT components and two performance measures, supply chain competency and organizational performance. Two groups are used in the research, one group of five operations management academics and another group of 30 practicing operations managers working in U.S. manufacturing firms. An interpretive structural modelling methodology is used to develop alternative structural models. The academics’ data show JIT-information emerging as lynchpin of relationships, directly impacting all other JIT practices and both performance measures. The practitioners’ data indicates that all JIT practices and performance measures are interactive as components and outcomes. This study is the first to apply interpretive structural modelling to investigate the interplay among total-JIT components and the performance measures of supply chain competency and organizational performance. 相似文献
239.
Two new nonparametric common principal component model selection procedures based on bootstrap distributions of the vector correlations of all combinations of the eigenvectors from two groups are proposed. The performance of these methods is compared in a simulation study to the two parametric methods previously suggested by Flury in 1988, as well as modified versions of two nonparametric methods proposed by Klingenberg in 1996 and then by Klingenberg and McIntyre in 1998. The proposed bootstrap vector correlation distribution (BVD) method is shown to outperform all of the existing methods in most of the simulated situations considered. 相似文献
240.
Data envelopment analysis (DEA) and free disposal hull (FDH) estimators are widely used to estimate efficiency of production. Practitioners use DEA estimators far more frequently than FDH estimators, implicitly assuming that production sets are convex. Moreover, use of the constant returns to scale (CRS) version of the DEA estimator requires an assumption of CRS. Although bootstrap methods have been developed for making inference about the efficiencies of individual units, until now no methods exist for making consistent inference about differences in mean efficiency across groups of producers or for testing hypotheses about model structure such as returns to scale or convexity of the production set. We use central limit theorem results from our previous work to develop additional theoretical results permitting consistent tests of model structure and provide Monte Carlo evidence on the performance of the tests in terms of size and power. In addition, the variable returns to scale version of the DEA estimator is proved to attain the faster convergence rate of the CRS-DEA estimator under CRS. Using a sample of U.S. commercial banks, we test and reject convexity of the production set, calling into question results from numerous banking studies that have imposed convexity assumptions. Supplementary materials for this article are available online. 相似文献