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31.
We study the impact of emotions on real-world decisions made by loan officers by analyzing the loan conditions of loans granted immediately after a bank branch robbery. We find significant differences between the conditions of loans granted after a robbery and changes in loan conditions that occur contemporaneously at unaffected branches. In general, loan officers seem to adopt so-called avoidance behavior. In accordance with the literature on posttraumatic stress, their avoidance behavior is halved within 2 weeks following the robbery and the effect further varies depending on the presence, or absence, of a firearm during the robbery. (JEL G02, G2) 相似文献
32.
Steven Gil 《Visual Studies》2020,35(2-3):302-303
33.
The relative error in the usual estimator of a brand's market share is reformulated in terms of marketing parameters. Such error is shown to be influenced in an important way by market penetration, as well as by variation in brand and product category volume. Of particular interest is the result that the relative error does not depend on the actual share level. Using data from a marketing research firm that supplies share estimates to the health products industry, we find that the relative error may be substantial even when a large sample is available. An upper bound on this relative error is obtained using marketing parameters that can frequently be measured using industry data and a company's internal records, thus reducing the level of judgmental input required in the planning of sample surveys. 相似文献
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Steven Martin 《Demography》2009,46(1):203-208
This analysis joins the debate on how declines in marriage have shifted the composition of the unmarried and married populations
in the United States, and how compositional shifts have affected nonmarital birth rates. Gray, Stockard, and Stone (2006)
presented one model for compositional effects that Ermisch (2009) challenged with alternative statistical tests. I propose
an alternative model for compositional shifts based not on theory but on observed marriage and fertility patterns. The results
from this alternative model are consistent with Ermisch’s findings yet support Gray et al.’s general case that compositional
effects have had an important infiuence on nonmarital birth rates. 相似文献
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Christopher R. Heathcote Borek D. Puza Steven P. Roberts 《Australian & New Zealand Journal of Statistics》2009,51(4):481-497
We consider two related aspects of the study of old‐age mortality. One is the estimation of a parameterized hazard function from grouped data, and the other is its possible deceleration at extreme old age owing to heterogeneity described by a mixture of distinct sub‐populations. The first is treated by half of a logistic transform, which is known to be free of discretization bias at older ages, and also preserves the increasing slope of the log hazard in the Gompertz case. It is assumed that data are available in the form published by official statistical agencies, that is, as aggregated frequencies in discrete time. Local polynomial modelling and weighted least squares are applied to cause‐of‐death mortality counts. The second, related, problem is to discover what conditions are necessary for population mortality to exhibit deceleration for a mixture of Gompertz sub‐populations. The general problem remains open but, in the case of three groups, we demonstrate that heterogeneity may be such that it is possible for a population to show decelerating mortality and then return to a Gompertz‐like increase at a later age. This implies that there are situations, depending on the extent of heterogeneity, in which there is at least one age interval in which the hazard function decreases before increasing again. 相似文献
38.
Urbanization and development are predicted to increase considerably in the United States over the next several decades, and
this is expected to result in large-scale habitat loss, fragmentation and loss of wildlife species. Thus, natural parks and
preserves are becomingly increasingly important in the conservation of regional biodiversity. We used mist-nets and AnabatII
acoustic detectors to survey bats in 10 national parks in the southeastern U.S. and examined the relationship between bat
community structure and development in the surrounding 5 km. We predicted that species richness would increase with park size
and that species richness and evenness would decrease with development. Species richness was not related to development or
any other landscape characteristics including park size. In contrast, species evenness declined with increasing development.
Percent Developed land in the surrounding 5 km area was the only variable that entered into the stepwise regression model.
The decrease in species evenness in the urban parks was due to the dominance of big brown bats (Eptesicus fuscus) in these parks. The percentage of big brown bats in our captures was positively related to percent Developed land in the
surrounding area. Our data suggest that urban parks may be important for conserving regional bat biodiversity. However, the
low species evenness in these parks suggests that some bat species may be susceptible to the effects of urbanization and may
be extirpated over time. Thus, management of urban as well as rural parks should strive to conserve as much bat roosting and
foraging habitat as possible. 相似文献
39.
Estimates of subgroup treatment effects in overall nonsignificant trials: To what extent should we believe in them? 下载免费PDF全文
Julien Tanniou Ingeborg van der Tweel Steven Teerenstra Kit C.B. Roes 《Pharmaceutical statistics》2017,16(4):280-295
In drug development, it sometimes occurs that a new drug does not demonstrate effectiveness for the full study population but appears to be beneficial in a relevant subgroup. In case the subgroup of interest was not part of a confirmatory testing strategy, the inflation of the overall type I error is substantial and therefore such a subgroup analysis finding can only be seen as exploratory at best. To support such exploratory findings, an appropriate replication of the subgroup finding should be undertaken in a new trial. We should, however, be reasonably confident in the observed treatment effect size to be able to use this estimate in a replication trial in the subpopulation of interest. We were therefore interested in evaluating the bias of the estimate of the subgroup treatment effect, after selection based on significance for the subgroup in an overall “failed” trial. Different scenarios, involving continuous as well as dichotomous outcomes, were investigated via simulation studies. It is shown that the bias associated with subgroup findings in overall nonsignificant clinical trials is on average large and varies substantially across plausible scenarios. This renders the subgroup treatment estimate from the original trial of limited value to design the replication trial. An empirical Bayesian shrinkage method is suggested to minimize this overestimation. The proposed estimator appears to offer either a good or a conservative correction to the observed subgroup treatment effect hence provides a more reliable subgroup treatment effect estimate for adequate planning of future studies. 相似文献
40.