全文获取类型
收费全文 | 2214篇 |
免费 | 85篇 |
专业分类
管理学 | 288篇 |
民族学 | 22篇 |
人口学 | 179篇 |
丛书文集 | 17篇 |
教育普及 | 1篇 |
理论方法论 | 245篇 |
综合类 | 16篇 |
社会学 | 1259篇 |
统计学 | 272篇 |
出版年
2023年 | 19篇 |
2022年 | 10篇 |
2021年 | 16篇 |
2020年 | 40篇 |
2019年 | 67篇 |
2018年 | 60篇 |
2017年 | 73篇 |
2016年 | 63篇 |
2015年 | 51篇 |
2014年 | 76篇 |
2013年 | 414篇 |
2012年 | 69篇 |
2011年 | 71篇 |
2010年 | 61篇 |
2009年 | 44篇 |
2008年 | 53篇 |
2007年 | 49篇 |
2006年 | 67篇 |
2005年 | 70篇 |
2004年 | 64篇 |
2003年 | 46篇 |
2002年 | 62篇 |
2001年 | 50篇 |
2000年 | 36篇 |
1999年 | 43篇 |
1998年 | 33篇 |
1997年 | 28篇 |
1996年 | 41篇 |
1995年 | 29篇 |
1994年 | 30篇 |
1993年 | 35篇 |
1992年 | 27篇 |
1991年 | 28篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 20篇 |
1987年 | 25篇 |
1986年 | 31篇 |
1985年 | 17篇 |
1984年 | 18篇 |
1983年 | 20篇 |
1982年 | 19篇 |
1981年 | 20篇 |
1980年 | 17篇 |
1979年 | 22篇 |
1978年 | 16篇 |
1977年 | 10篇 |
1976年 | 20篇 |
1975年 | 23篇 |
1973年 | 12篇 |
排序方式: 共有2299条查询结果,搜索用时 15 毫秒
51.
Kate Pride Brown 《Social movement studies》2016,15(6):547-560
This article aims to articulate a new agenda in the scholarship of social movements. Specifically, it seeks to turn attention to the assumptions that undergird activism. Rather than studying movements themselves, we can study them as the embodiment of collective expectation in a particular public. We can learn more about the broader society in which movements are embedded by asking how activists and the public they seek to engage determine what is within the realm of possibility. I refer to the imagined horizon of possibility as the activist prospectus. To illustrate the importance of prospectus, I draw upon a case study of environmental activism in Samara, Russia. Ethnographic observation and analysis yield insights into subjective perceptions that help explain the weakness of civil society within Russia. 相似文献
52.
The Value of Information in Decision‐Analytic Modeling for Malaria Vector Control in East Africa
下载免费PDF全文
![点击此处可从《Risk analysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dohyeong Kim Zachary Brown Richard Anderson Clifford Mutero Marie Lynn Miranda Jonathan Wiener Randall Kramer 《Risk analysis》2017,37(2):231-244
Decision analysis tools and mathematical modeling are increasingly emphasized in malaria control programs worldwide to improve resource allocation and address ongoing challenges with sustainability. However, such tools require substantial scientific evidence, which is costly to acquire. The value of information (VOI) has been proposed as a metric for gauging the value of reduced model uncertainty. We apply this concept to an evidenced‐based Malaria Decision Analysis Support Tool (MDAST) designed for application in East Africa. In developing MDAST, substantial gaps in the scientific evidence base were identified regarding insecticide resistance in malaria vector control and the effectiveness of alternative mosquito control approaches, including larviciding. We identify four entomological parameters in the model (two for insecticide resistance and two for larviciding) that involve high levels of uncertainty and to which outputs in MDAST are sensitive. We estimate and compare a VOI for combinations of these parameters in evaluating three policy alternatives relative to a status quo policy. We find having perfect information on the uncertain parameters could improve program net benefits by up to 5–21%, with the highest VOI associated with jointly eliminating uncertainty about reproductive speed of malaria‐transmitting mosquitoes and initial efficacy of larviciding at reducing the emergence of new adult mosquitoes. Future research on parameter uncertainty in decision analysis of malaria control policy should investigate the VOI with respect to other aspects of malaria transmission (such as antimalarial resistance), the costs of reducing uncertainty in these parameters, and the extent to which imperfect information about these parameters can improve payoffs. 相似文献
53.
Edward E. Gbur 《统计学通讯:模拟与计算》2013,42(5):531-535
A commonly used statistic for testing hypotheses concerning count data is the index of dispersion or variance test (c.f., Fisher 1950, Rao and Chakravarti 1956). The statistic is essentially the ratio of the sample variance to the sample mean,The hypothesis being tested is commonly referred to as the homogeneity hypothesis, often without further detailed specification. However, a closer study of the literature indicates that there are really two different hypotheses of interest. 相似文献
54.
The spread of an emerging infectious disease is a major public health threat. Given the uncertainties associated with vector-borne diseases, in terms of vector dynamics and disease transmission, it is critical to develop statistical models that address how and when such an infectious disease could spread throughout a region such as the USA. This paper considers a spatio-temporal statistical model for how an infectious disease could be carried into the USA by migratory waterfowl vectors during their seasonal migration and, ultimately, the risk of transmission of such a disease to domestic fowl. Modeling spatio-temporal data of this type is inherently difficult given the uncertainty associated with observations, complexity of the dynamics, high dimensionality of the underlying process, and the presence of excessive zeros. In particular, the spatio-temporal dynamics of the waterfowl migration are developed by way of a two-tiered functional temporal and spatial dimension reduction procedure that captures spatial and seasonal trends, as well as regional dynamics. Furthermore, the model relates the migration to a population of poultry farms that are known to be susceptible to such diseases, and is one of the possible avenues toward transmission to domestic poultry and humans. The result is a predictive distribution of those counties containing poultry farms that are at the greatest risk of having the infectious disease infiltrate their flocks assuming that the migratory population was infected. The model naturally fits into the hierarchical Bayesian framework. 相似文献
55.
Research shows that those with greater social capital enjoy better physical and mental health. The current study illuminates a paradox of social capital which may afflict those involved in traumatic events. Several years of survey data reveal a dynamic picture of the link between social capital and stress following Hurricane Katrina. Results reveal that initially after Katrina, those who were more socially embedded carried the greatest load with respect to helping the displaced population, thus experiencing more stress. But over time, the most socially-involved then snapped back from their stressful experiences more rapidly than isolates. This confirms that over the course of stressful events, social involvement first exposes people to more stress, but as time passes, provides them a significant buffer against negative psychosocial experiences. 相似文献
56.
57.
We consider assortment problems under a mixture of multinomial logit models. There is a fixed revenue associated with each product. There are multiple customer types. Customers of different types choose according to different multinomial logit models whose parameters depend on the type of the customer. The goal is to find a set of products to offer so as to maximize the expected revenue obtained over all customer types. This assortment problem under the multinomial logit model with multiple customer types is NP‐complete. Although there are heuristics to find good assortments, it is difficult to verify the optimality gap of the heuristics. In this study, motivated by the difficulty of finding optimal solutions and verifying the optimality gap of heuristics, we develop an approach to construct an upper bound on the optimal expected revenue. Our approach can quickly provide upper bounds and these upper bounds can be quite tight. In our computational experiments, over a large set of randomly generated problem instances, the upper bounds provided by our approach deviate from the optimal expected revenues by 0.15% on average and by less than one percent in the worst case. By using our upper bounds, we are able to verify the optimality gaps of a greedy heuristic accurately, even when optimal solutions are not available. 相似文献
58.
Techniques used in variability assessment are subsequently used to draw conclusions regarding the “spread”/uniformity of data curves. Due to the limitations of these techniques, they are not adequate for circumstances where data manifest with multiple peaks. Examples of these manifestations (in three-dimensional space) include under-foot pressure distributions recorded for different types of footwear (Becerro-de-Bengoa-Vallejo et al., 2014; Cibulka et al., 1994; Davies et al., 2003), surface textures and interfaces designed to impact friction, and and and molecular surface structures such as viral epitopes (Torras and Garcia-Valls, 2004; Pacejka, 1997; Fustaffson, 1997). This article proposes a technique for generating a single variable – Λ that will quantify the uniformity of such surfaces. We define and validate this technique using several mathematical and graphical models. 相似文献
59.
One in five students report experimenting with tobacco before the age of 13 and most prevention efforts take place in the school setting. This study measures the effect of a single-lesson tobacco prevention curriculum, conducted by a health education center, focusing on knowledge of tobacco, ability to identify refusal techniques, and intent not to smoke. Data were collected, via electronic keypads, from students visiting a non-school, health education center in Michigan (n = 704 intervention and 85 comparison). Contingency table Chi-squared tests and t-tests demonstrated that a single lesson can improve general knowledge and ability to identify appropriate refusal techniques. Improvement in intent not to smoke was not significant because both groups had very high intent prior to implementation. Similar to results from other programs, multivariate logistic regression of gender, general knowledge, and skill identification revealed that only the skill variable was associated with intent not to smoke at pretest. Recommendations are given for further research and for designing more effective curricula or programs. 相似文献
60.
Davis LW Strasburger AM Brown LF 《Journal of psychosocial nursing and mental health services》2007,45(11):23-29
Despite evidence that individuals with schizophrenia spectrum disorders experience significant and persistent symptoms of anxiety, there are few reports of the use of empirically supported treatments for anxiety in this population. This article describes how we have tried to adapt mindfulness interventions to help individuals with schizophrenia who experience significant anxiety symptoms. Although mindfulness has been widely used to help individuals without psychosis, to our knowledge, this is the first study adapting it to help those with schizophrenia manage worry and stress. We provide an overview of the intervention and use an individual example to describe how our treatment development group responded. We also explore directions for future research of mindfulness interventions for schizophrenia. 相似文献