首页 | 本学科首页   官方微博 | 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   3656篇
  免费   98篇
管理学   560篇
民族学   32篇
人才学   1篇
人口学   338篇
丛书文集   31篇
理论方法论   345篇
综合类   21篇
社会学   1892篇
统计学   534篇
  2023年   18篇
  2021年   23篇
  2020年   54篇
  2019年   77篇
  2018年   77篇
  2017年   98篇
  2016年   93篇
  2015年   81篇
  2014年   79篇
  2013年   695篇
  2012年   92篇
  2011年   108篇
  2010年   90篇
  2009年   75篇
  2008年   115篇
  2007年   114篇
  2006年   80篇
  2005年   92篇
  2004年   91篇
  2003年   90篇
  2002年   116篇
  2001年   84篇
  2000年   82篇
  1999年   64篇
  1998年   58篇
  1997年   58篇
  1996年   45篇
  1995年   61篇
  1994年   54篇
  1993年   50篇
  1992年   45篇
  1991年   52篇
  1990年   42篇
  1989年   40篇
  1988年   59篇
  1987年   57篇
  1986年   26篇
  1985年   39篇
  1984年   46篇
  1983年   57篇
  1982年   32篇
  1981年   35篇
  1980年   29篇
  1979年   34篇
  1978年   39篇
  1977年   31篇
  1976年   35篇
  1975年   28篇
  1974年   18篇
  1972年   17篇
排序方式: 共有3754条查询结果,搜索用时 0 毫秒
991.
Within the last 10 years, technological advances have allowed personal wireless communications to become part of our global, information-centric culture. Cellular telephones, personal digital assistants, and wireless computer networks allow for tetherless use anytime and almost anywhere. These wireless communication advances have quickly matured through three technological generations. Currently, wireless communications are considered to be in the third generation (3G) of deployment and are rapidly approaching the fourth (4G). As these wireless technologies advance to meet market demand, careful pre-market technical analysis of these new capabilities must be made to understand potential impact on existing communication systems. This paper provides a novel examination into the effects of 4G ultrawide band (UWB) signaling on a 3G wireless fidelity (WiFi) system. Through empirical and statistical analyses, we show that the throughput performance of the Wi-Fi system can be negatively impacted by up to 20%. We conclude that careful implementation of emerging 4G UWB systems must occur to mitigate the detriments to existing 3G communication systems.  相似文献   
992.
Although nanotechnology is broadly receiving attention in public and academic circles, oversight issues associated with applications for agriculture and food remain largely unexplored. Agrifood nanotechnology is at a critical stage in which informed analysis can help shape funding priorities, risk assessment, and oversight activities. This analysis is designed to help society and policymakers anticipate and prepare for challenges posed by complicated, convergent applications of agrifood nanotechnology. The goal is to identify data, risk assessment, regulatory policy, and engagement needs for overseeing these products so they can be addressed prior to market entry. Our approach, termed upstream oversight assessment (UOA), has potential as a key element of anticipatory governance. It relies on distinct case studies of proposed applications of agrifood nanotechnology to highlight areas that need study and attention. As a tool for preparation, UOA anticipates the types and features of emerging applications; their endpoints of use in society; the extent to which users, workers, ecosystems, or consumers will be exposed; the nature of the material and its safety; whether and where the technologies might fit into current regulatory system(s); the strengths and weaknesses of the system(s) in light of these novel applications; and the possible social concerns related to oversight for them.  相似文献   
993.
The case-based approach to learning is popular among many applied fields. However, results of case-based education vary widely on case content and case presentation. This study examined two aspects of case-based education—outcome valence and case elaboration methods—in a two-day case-based Responsible Conduct of Research (RCR) ethics education program. Results suggest that outcome information is an integral part of a quality case. Furthermore, valence consistent outcomes may have certain advantages over mixed valence outcome information. Finally, students enjoy and excel working with case material, and the use of elaborative interrogation techniques can significantly improve internally-focused ethical sensemaking strategies associated with personal biases, constraints, and emotions.  相似文献   
994.
995.
996.
Service learning is a teaching strategy that involves engaging in a mutually beneficial partnership between a community and students in the classroom. Social work education and service learning share core values of service and social justice and, when unified, can offer students unique opportunities to engage in meaningful application of knowledge and skills in a real-world setting. This article provides an exemplar describing the unique student learning outcomes that resulted from a service learning partnership between graduate-level social work students in a diversity course and a community health clinic serving Latino immigrants and Burmese refugees.  相似文献   
997.
This paper examines Bayesian posterior probabilities as a function of selected elements within the set of data, x, when the prior distribution is assumed fixed. The posterior probabilities considered here are those of the parameter vector lying in a subset of the total parameter space. The theorems of this paper provide insight into the effect of elements within x on this posterior probability. These results have applications, for example, in the study of the impact of outliers within the data and in the isolation of misspecified parameters in a model.  相似文献   
998.
The author examined the way students enrolled in the Introductory Human Geography course at Kansas State University described their hometowns using the location theme of geography. Participants completed this task as a required take-home assignment. Because the majority of students were from Kansas, the author presents results from locations of Kansas hometowns in this article. Students seemed to prefer to use relative location rather than absolute location to describe their hometowns. Realizing that expressing relative location only in one way may not be sufficient, students described relative location in numerous ways. In doing so, students provided interesting information and new insights about the place theme of geography. They also analyzed how absolute and relative location are subject to change over time. Through this assignment, students realized the importance of location and the significance of interactions of places of different sizes.  相似文献   
999.
The Gambling Passion Scale (GPS) is a recently developed research instrument for assessing individuals' passion for gambling. Because the psychometric properties of the GPS have only previously been examined in French Canadians, the aim of this study was to replicate previous psychometric findings in an English-speaking university sample. Participants (female: n = 58; male: n = 89) were drawn from a university campus based on self-reported experience with gambling indexed by scores on the South Oaks Gambling Screen (SOGS). The two-factor structure reported by Rousseau et al. (Journal of Gambling Studies, 18(1), pp. 45–66, 2002) was largely replicated in this sample, as were relationships between ‘obsessive passion’ and negative consequences stemming from gambling. These results support the validity of the GPS as a measure of gambling passion in English-speaking university gamblers and its potential to contribute to understanding problem gambling.  相似文献   
1000.
The present study examined the relationship between gender and drug-use among adolescents using diagnostic assessments and biochemical analyses of urine samples. The data were collected in the context of a referral and assessment program for adolescents suspected of using drugs, using the Adolescent Substance Battery [1]. A six-month random sample of 20 percent of adolescents assessed for drug use were targeted for biochemical assay. Compliance for urine delivery was relatively high at 91 percent. Urine samples were quantitatively screened for pharmaceuticals using a standard thin-layer chromatography (TLC) technique [2]. Statistical significance was found in the relationship between gender and marijuana use (p < .05). This study confirms that gender and drug-using behaviors among adolescents need additional research and evaluation.  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