全文获取类型
收费全文 | 2183篇 |
免费 | 69篇 |
专业分类
管理学 | 200篇 |
民族学 | 12篇 |
人口学 | 233篇 |
丛书文集 | 3篇 |
理论方法论 | 294篇 |
综合类 | 15篇 |
社会学 | 1324篇 |
统计学 | 171篇 |
出版年
2023年 | 16篇 |
2022年 | 9篇 |
2021年 | 14篇 |
2020年 | 45篇 |
2019年 | 55篇 |
2018年 | 58篇 |
2017年 | 74篇 |
2016年 | 67篇 |
2015年 | 41篇 |
2014年 | 60篇 |
2013年 | 350篇 |
2012年 | 82篇 |
2011年 | 97篇 |
2010年 | 62篇 |
2009年 | 53篇 |
2008年 | 72篇 |
2007年 | 81篇 |
2006年 | 90篇 |
2005年 | 79篇 |
2004年 | 74篇 |
2003年 | 70篇 |
2002年 | 66篇 |
2001年 | 54篇 |
2000年 | 63篇 |
1999年 | 38篇 |
1998年 | 33篇 |
1997年 | 30篇 |
1996年 | 30篇 |
1995年 | 22篇 |
1994年 | 38篇 |
1993年 | 23篇 |
1992年 | 29篇 |
1991年 | 28篇 |
1990年 | 16篇 |
1989年 | 18篇 |
1988年 | 14篇 |
1987年 | 19篇 |
1986年 | 17篇 |
1985年 | 16篇 |
1984年 | 22篇 |
1983年 | 16篇 |
1982年 | 10篇 |
1981年 | 9篇 |
1980年 | 16篇 |
1979年 | 8篇 |
1978年 | 11篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1971年 | 6篇 |
排序方式: 共有2252条查询结果,搜索用时 140 毫秒
261.
Foot-and-mouth disease (FMD) is a viral disease of domesticated and wild cloven-hoofed animals. FMD virus is known to spread by direct contact between infected and susceptible animals, by animal products such as meat and milk, by the airborne route, and mechanical transfer on people, wild animals, birds, and by vehicles. During the outbreak of 2001 in the Netherlands, milk from dairy cattle was illegally discharged into the sewerage as a consequence of transport prohibition. This may lead to contaminated discharges of biologically treated and raw sewage in surface water that is given to cattle to drink. The objective of the present study was to assess the probability of infecting dairy cows that were drinking FMD virus contaminated surface water due to illegal discharges of contaminated milk. So, the following data were collected from literature: FMD virus inactivation in aqueous environments, FMD virus concentrations in milk, dilution in sewage water, virus removal by sewage treatment, dilution in surface water, water consumption of cows, size of a herd in a meadow, and dose-response data for ingested FMD virus by cattle. In the case of 1.6 x 10(2) FMD virus per milliliter in milk and discharge of treated sewage in surface water, the probability of infecting a herd of cows was estimated to be 3.3 x 10(-7) to 8.5 x 10(-5), dependent on dilution in the receiving surface water. In the case of discharge of raw sewage, all probabilities of infection were 100 times higher. In the case of little dilution in small rivers, the high level of 8.5 x 10(-3) is reached. For 10(4) times higher FMD virus concentrations in milk, the probabilities of infecting a herd of cows are high in the case of discharge of treated sewage (3.3 x 10(-3) to 5.7 x 10(-1)) and very high in the case of discharge of raw sewage (0.28-1.0). It can be concluded that illegal and uncontrolled discharges of contaminated milk into the sewerage system may lead to high risks to other cattle farms at 6-50 km distance of the location of discharge within one day. This clearly underlines current measures that prohibit such discharges, and also asks for strict control. This risk assessment clearly demonstrated the potential significance of FMD virus transmission via water, and the results will be useful on an international scale, and could also serve as a basis for other FMD risk-assessment models. 相似文献
262.
Timing of first fatherhood was examined in a sample of 206 at-risk, predominantly White men, followed prospectively for 17 years. An event history analysis was used to test a model wherein antisocial behavior, the contextual and familial factors that may contribute to the development of antisocial behavior, and common correlates of such behavior, including academic failure, substance use, and early initiation of sexual behaviors, lead both directly and indirectly to an early transition to fatherhood. Having a mother who was younger at first birth, low family SES, poor academic skills, failure to use condoms, and being in a cohabitating or marital relationship predicted entry into fatherhood. Implications of the findings for prevention of and intervention with early fathering are discussed. 相似文献
263.
264.
265.
The Analysis of Verbal Behavior - 相似文献
266.
Judith A. Fortney Saad Gadalla Saneya Saleh Inne Susanti Malcolm Potts Susan M. Rogers 《Population research and policy review》1987,6(2):137-148
Data on cause of death are deficient for most developing countries. Nevertheless, it is important for policy makers to have access to such information to plan the use of resources and to evaluate health programs. In this study, deaths among women of reproductive age (15 to 49) in two areas in developing countries were located, and family members were interviewed. Local physicians reviewed the completed interviews and determined the cause of death.Complications of pregnancy and childbirth were the cause of 23% of the deaths in Menoufia, Egypt and Bali, Indonesia. In Egypt, the first cause of death was circulatory system disease (28%), followed by complications of pregnancy and childbirth (23%), and trauma (14%, primarily burns). In Indonesia, complications of pregnancy and childbirth was the first cause of death, followed by infectious disease (22%, primarily tuberculosis), and circulatory system disease (13%).Although the method of data collection was unorthodox, findings for Menoufia are comparable to data from other sources for the country as a whole. There are few data with which to compare our findings for Bali, but their similarity to the data from the Egyptian study lends credence to their quality. 相似文献
267.
268.
Gambling in young adolescents 总被引:1,自引:1,他引:0
Susan G. Ide-Smith Stephen E. G. Lea 《Journal of gambling studies / co-sponsored by the National Council on Problem Gambling and Institute for the Study of Gambling and Commercial Gaming》1988,4(2):110-118
A questionnaire was used to investigate gambling in British adolescents. Responses from fifty 13- to 14-year-olds were analyzed. Gambling was found to be very pervasive (90% of subjects reported at least some gambling activity). Males gambled more than females, both in absolute terms and as a proportion of income. Income was found to have some influence on gambling behavior, but the effects of intelligence and social class were nonsignificant. Slot machines were the commonest form of gambling in both sexes.The willing cooperation of the teacher and students concerned is gratefully acknowledged. This paper is based on a report submitted by the first author in partial fulfillment of the requirements for the BSc degree at the University of Exeter. Some of the data were presented to the conference of the British Psychological Society Developmental Section, held in Exeter in September 1986, and to the colloquium of the International Association for Research in Economic Psychology, held at Aarhus, Denmark, in September 1987. 相似文献
269.
Susan Schwochau 《Journal of Labor Research》1994,15(4):331-354
A framework for analyzing the determinants of state labor relations policies is developed using the notion of tactics. Unions
and management have various tactical options, at both the state and local levels, for influencing employment outcomes. The
framework explicitly recognizes those options, and thus incorporates actions, such as bringing cases to courts, which have
received little attention in previous research. Consideration of local-level tactics reveals additional factors that may influence
interest group incentives to seek state-level policy changes.
The author thanks Paul Jarley, John Delaney, Jim Bennett, and George Neumann for helpful comments on earlier drafts of this
paper. This paper was partially supported by a University of Iowa Old Gold Summer Research Fellowship and a College of Business
Administration Summer Research Grant. 相似文献
270.
The Analysis of Verbal Behavior - The behavioral effects of environmental events can be classified as evocative when we refer to an immediate but momentary change in behavior, and as... 相似文献