全文获取类型
收费全文 | 8368篇 |
免费 | 209篇 |
国内免费 | 2篇 |
专业分类
管理学 | 1261篇 |
民族学 | 25篇 |
人口学 | 738篇 |
丛书文集 | 22篇 |
理论方法论 | 753篇 |
综合类 | 98篇 |
社会学 | 4277篇 |
统计学 | 1405篇 |
出版年
2020年 | 111篇 |
2019年 | 150篇 |
2018年 | 159篇 |
2017年 | 192篇 |
2016年 | 171篇 |
2015年 | 125篇 |
2014年 | 169篇 |
2013年 | 1446篇 |
2012年 | 206篇 |
2011年 | 217篇 |
2010年 | 165篇 |
2009年 | 156篇 |
2008年 | 198篇 |
2007年 | 193篇 |
2006年 | 206篇 |
2005年 | 196篇 |
2004年 | 165篇 |
2003年 | 138篇 |
2002年 | 153篇 |
2001年 | 170篇 |
2000年 | 189篇 |
1999年 | 161篇 |
1998年 | 151篇 |
1997年 | 136篇 |
1996年 | 140篇 |
1995年 | 141篇 |
1994年 | 153篇 |
1993年 | 140篇 |
1992年 | 156篇 |
1991年 | 168篇 |
1990年 | 174篇 |
1989年 | 149篇 |
1988年 | 159篇 |
1987年 | 143篇 |
1986年 | 137篇 |
1985年 | 140篇 |
1984年 | 148篇 |
1983年 | 132篇 |
1982年 | 99篇 |
1981年 | 82篇 |
1980年 | 90篇 |
1979年 | 115篇 |
1978年 | 92篇 |
1977年 | 71篇 |
1976年 | 81篇 |
1975年 | 54篇 |
1974年 | 77篇 |
1973年 | 54篇 |
1971年 | 43篇 |
1970年 | 44篇 |
排序方式: 共有8579条查询结果,搜索用时 125 毫秒
271.
Communities across the nation have become increasingly concerned about inhalant use and use of harmful legal products among youth because of increasing prevalence rates and deleterious health consequences from abusing these products. The increasing concern of communities about inhaling and ingesting legal products has been coupled with increasing awareness and concern about ability of youth to access and abuse a variety of other legal retail products. There are few examples of scientifically designed community prevention projects that seek to reduce youth abuse of such legal products. This article describes a community prevention trial that is designed to reduce sales of inhalants and other harmful legal products to youth and demonstrates how the retailer component of the trial can be rigorously evaluated. It also shows how data from youth purchase attempts can complement survey data from retailers. 相似文献
272.
In recent years, a variety of regression models, including zero-inflated and hurdle versions, have been proposed to explain the case of a dependent variable with respect to exogenous covariates. Apart from the classical Poisson, negative binomial and generalised Poisson distributions, many proposals have appeared in the statistical literature, perhaps in response to the new possibilities offered by advanced software that now enables researchers to implement numerous special functions in a relatively simple way. However, we believe that a significant research gap remains, since very little attention has been paid to the quasi-binomial distribution, which was first proposed over fifty years ago. We believe this distribution might constitute a valid alternative to existing regression models, in situations in which the variable has bounded support. Therefore, in this paper we present a zero-inflated regression model based on the quasi-binomial distribution, taking into account the moments and maximum likelihood estimators, and perform a score test to compare the zero-inflated quasi-binomial distribution with the zero-inflated binomial distribution, and the zero-inflated model with the homogeneous model (the model in which covariates are not considered). This analysis is illustrated with two data sets that are well known in the statistical literature and which contain a large number of zeros. 相似文献
273.
274.
Multiple-predictor empirical and single-predictor judgment-based models represent the two basic types of sales-force decision models (SDMs). The important similarities and differences between the two modeling approaches are identified and discussed. The SDM literature is reviewed to determine how each model type has been applied and to evaluate previous attempts at model validation. A research study designed to compare the normative sales-call allocations generated from each modeling approach is presented. Study results indicate that empirical and judgment-based SDMs would produce similar normative guidelines. The implications of this finding are discussed. 相似文献
275.
The Japanese “just-in-time with kanban” technique reduces in-process inventory to absolute minimal levels, in concert with the Japanese belief that inventory is an unnecessary evil. Due to the success of Japanese firms that employ this type of system, American firms would like to import this technique and emulate Japanese successes. But this Japanese success may be attributable not only to the just-in-time with kanban technique but also to the production environment in which the technique is employed. This paper simulates the just-in-time with kanban technique for a multiline, multistage production system in order to determine its adaptability to an American production environment that might include such characteristics as variable processing times, variable master production scheduling, and imbalances between production stages. The results have practical implications for those firms considering adoption of the Japanese technique. 相似文献
276.
Environmental scanning activities of over 400 top management subunits in 108 European manufacturing firms provided the data base for this research. Four traits (constructs) of scanning using three methods (interest, frequency, and time) were examined. A confirmatory factor analysis approach to multitrait-multimethod (MTMM) data was employed. Verification of the reliability as well as convergent and discriminant validity of the scanning scales are reported and discussed. The viability of confirmatory factor analysis in providing a precise analysis of partitioning variance according to trait, method, and error is demonstrated. 相似文献
277.
This paper describes a case that examines five key topics in production and operations management [1]—forecasting, inventory control, transportation planning, aggregate planning, and the disaggregation of the aggregate plan—in an integrated, realistic manner for upper-level undergraduate business majors [3]. The case structure stresses the linkage of these interrelated subjects and supplements the regular classroom presentations dealing with them. The case relies on computer calculations at each stage to provide the information input for calculations at the next stage. It is a static model with a twelve-month planning horizon. Students complete several exercises and assume several roles as the case unfolds. They act on their own in filling some roles and as members of teams in performing others. They do not compete with each other, as the purpose of the case is to help them develop an appreciation of the factors that persons performing the role must consider. 相似文献
278.
279.
280.
Unmet need for family planning has been a core concept in international population discourse for several decades. This article reviews the history of unmet need and the development of increasingly refined methods of its empirical measurement and delineates the main questions that have been raised about unmet need during the past decade, some of which concern the validity of the concept and others its role in policy debates. The discussion draws heavily on empirical research conducted during the 1990s, much of it localized, in‐depth studies combining quantitative and qualitative methodologies. Of the causes of unmet need other than those related to access to services, three emerge as especially salient: lack of necessary knowledge about contraceptive methods, social opposition to their use, and health concerns about possible side effects. The article argues that the concept of unmet need for family planning, by joining together contraceptive behavior and fertility preferences, encourages an integration of family planning programs and broader development approaches to population policy. By focusing on the fulfillment of individual aspirations, unmet need remains a defensible rationale for the formulation of population policy and a sensible guide to the design of family planning programs. 相似文献