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   626篇
  免费   34篇
管理学   56篇
民族学   10篇
人口学   64篇
丛书文集   3篇
理论方法论   47篇
综合类   27篇
社会学   338篇
统计学   115篇
  2023年   13篇
  2022年   10篇
  2021年   16篇
  2020年   29篇
  2019年   26篇
  2018年   36篇
  2017年   47篇
  2016年   31篇
  2015年   18篇
  2014年   24篇
  2013年   91篇
  2012年   130篇
  2011年   23篇
  2010年   18篇
  2009年   15篇
  2008年   11篇
  2007年   12篇
  2006年   12篇
  2005年   7篇
  2004年   11篇
  2003年   8篇
  2002年   15篇
  2001年   11篇
  2000年   10篇
  1999年   4篇
  1998年   2篇
  1997年   5篇
  1996年   3篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   6篇
  1990年   2篇
  1987年   2篇
  1985年   2篇
  1983年   1篇
  1980年   1篇
  1975年   2篇
排序方式: 共有660条查询结果,搜索用时 15 毫秒
1.
Urban Ecosystems - The development of urban areas imposes challenges that wildlife must adapt to in order to persist in these new habitats. One of the greatest changes brought by urbanization has...  相似文献   
2.
The emerging digital transformation in the twenty‐first century is rapidly and significantly changing the business landscape. The fast‐changing activities, expectations and new modes of collaboration suggest it is time to review the current theoretical insights from strategic alliance (SA) research, which are based on assumptions from a different era. We therefore aim to stimulate multidisciplinary debate and theoretical reflections to better understand emerging paradoxes and challenges that contemporary firms face in the formation, evolution and dissolution of strategic alliances. Specifically, we offer alternative visions of SA research and suggest fresh applications or supplements of existing theoretical perspectives and research methods that can better address the research questions emerging from an era of digital transformation.  相似文献   
3.
National Park of Tijuca in Rio de Janeiro (Brazil) is about 3,300 ha and considered the largest urban forest in the world. Its floristic composition is typical of Atlantic Rain Forest. The reserve is being altered because of fire occurrences and urban expansion. This study identified locations and causes of forest fires, and makes management recommendations to restore damaged areas. From 1991 to 2000, forest firefighters recorded an average of 75-fire occurrences/year. Identified causes included hot air balloons (24%), intentional (24%), rubbish burning (21%) and religious practices (17%). Primary fuels included invasive grasses and ferns. Although hot air balloons destroyed larger areas of forest in each occurrence, a greater number of fires started in the invasive vegetation along roads that bisect the forest. In response to recurrent forests, invasive vegetation has spread gradually into the forest increasing forest degradation. To decrease fire damage, sites with high fire frequencies and density of invasive vegetation were planted with less flammable species. Results indicate that fire frequency decreased and density of invasive vegetation declined. This approach appears to prevent fire incidence, reduce the need for fire fighting, and preserve existing biodiversity.  相似文献   
4.
5.
In a wide variety of biomedical and clinical research studies, sample statistics from diagnostic marker measurements are presented as a means of distinguishing between two populations, such as with and without disease. Intuitively, a larger difference between the mean values of a marker for the two populations, and a smaller spread of values within each population, should lead to more reliable classification rules based on this marker. We formalize this intuitive notion by deriving practical, new, closed-form expressions for the sensitivity and specificity of three different discriminant tests defined in terms of the sample means and standard deviations of diagnostic marker measurements. The three discriminant tests evaluated are based, respectively, on the Euclidean distance and the Mahalanobis distance between means, and a likelihood ratio analysis. Expressions for the effects of measurement error are also presented. Our final expressions assume that the diagnostic markers follow independent normal distributions for the two populations, although it will be clear that other known distributions may be similarly analyzed. We then discuss applications drawn from the medical literature, although the formalism is clearly not restricted to that application.  相似文献   
6.
Social capital has been considered a cause and consequence of various uses of new information and communication technologies (ICTs). However, there is a growing divergence between how social capital is commonly measured in the study of ICTs and how it is measured in other fields. This departure raises questions about the validity of some of the most widely cited studies of social capital and ICTs. We compare the Internet Social Capital Scales (ISCS) developed by Williams [2006. On and off the ’net: scales for social capital in an online era. Journal of Computer-Mediated Communication, 11(2), 593–628. doi: 10.1111/j.1083-6101.2006.00029.x] – a series of psychometric scales commonly used to measure ‘social capital’ – to established, structural measures of social capital: name, position, and resource generators. Based on a survey of 880 undergraduate students (the population to which the ISCS has been most frequently administered), we find that, unlike structural measures, the ISCS does not distinguish between the distinct constructs of bonding and bridging social capital. The ISCS does not have convergent validity with structural measures of bonding or bridging social capital; it does not measure the same concept as structural measures. The ISCS conflates social capital with the related constructs of social support and attachment. The ISCS does not measure perceived or actual social capital. These findings raise concerns about the interpretations of existing studies of ‘social capital’ and ICTs that are based on the ISCS. Given the absence of measurement validity, we urge those studying social capital to abandon the ISCS in favor of alternative approaches.  相似文献   
7.
The objective of meat inspection is to promote animal and public health by preventing, detecting, and controlling hazards originating from animals. With the improvements of sanitary level in pig herds, the hazards profile has shifted and the inspection procedures no longer target major foodborne pathogens (i.e., not risk based). Additionally, carcass manipulations performed when searching for macroscopic lesions can lead to cross‐contamination. We therefore developed a stochastic model to quantitatively describe cross‐contamination when consecutive carcasses are submitted to classic inspection procedures. The microbial hazard used to illustrate the model was Salmonella, the data set was obtained from Brazilian slaughterhouses, and some simplifying assumptions were made. The model predicted that due to cross‐contamination during inspection, the prevalence of contaminated carcass surfaces increased from 1.2% to 95.7%, whereas the mean contamination on contaminated surfaces decreased from 1 logCFU/cm² to ?0.87 logCFU/cm², and the standard deviations decreased from 0.65 to 0.19. These results are explained by the fact that, due to carcass manipulations with hands, knives, and hooks, including the cutting of contaminated lymph nodes, Salmonella is transferred to previously uncontaminated carcasses, but in small quantities. These small quantities can easily go undetected during sampling. Sensitivity analyses gave insight into the model performance and showed that the touching and cutting of lymph nodes during inspection can be an important source of carcass contamination. The model can serve as a tool to support discussions on the modernization of pig carcass inspection.  相似文献   
8.
Rape Jokes     
A curated selection of rape jokes taken from various Anglophone websites devoted to crowd-sourced offensive humor. Individual jokes may have been slightly modified to emphasize their poetic features.  相似文献   
9.
10.
Interoception, often defined as the perception of internal physiological changes, is implicated in many adult social affective processes, but its effects remain understudied in the context of parental socialization of children's emotions. We hypothesized that what parents know about the interoceptive concomitants of emotions, or interoceptive knowledge (e.g., “my heart races when excited”), may be especially relevant in emotion socialization and in supporting children's working models of emotions and the social world. We developed a measure of mothers' interoceptive knowledge about their own emotions and examined its relation to children's social affective outcomes relative to other socialization factors, including self‐reported parental behaviors, emotion beliefs, and knowledge of emotion‐relevant situations and non‐verbal expressions. To assess these, mothers (N = 201) completed structured interviews and questionnaires. A few months later, third‐grade teachers rated children's social skills and emotion regulation observed in the classroom. Results indicated that mothers' interoceptive knowledge about their own emotions was associated with children's social affective skills (emotion regulation, social initiative, cooperation, self‐control), even after controlling for child gender and ethnicity, family income, maternal stress, and the above maternal socialization factors. Overall, findings suggest that mothers' interoceptive knowledge may provide an additional, unique pathway by which children acquire social affective competence.  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