全文获取类型
收费全文 | 3506篇 |
免费 | 119篇 |
专业分类
管理学 | 438篇 |
民族学 | 34篇 |
人口学 | 426篇 |
丛书文集 | 20篇 |
理论方法论 | 259篇 |
综合类 | 161篇 |
社会学 | 1620篇 |
统计学 | 667篇 |
出版年
2024年 | 6篇 |
2023年 | 57篇 |
2022年 | 41篇 |
2021年 | 62篇 |
2020年 | 153篇 |
2019年 | 172篇 |
2018年 | 226篇 |
2017年 | 264篇 |
2016年 | 224篇 |
2015年 | 122篇 |
2014年 | 183篇 |
2013年 | 552篇 |
2012年 | 346篇 |
2011年 | 113篇 |
2010年 | 99篇 |
2009年 | 86篇 |
2008年 | 81篇 |
2007年 | 80篇 |
2006年 | 51篇 |
2005年 | 60篇 |
2004年 | 112篇 |
2003年 | 106篇 |
2002年 | 80篇 |
2001年 | 57篇 |
2000年 | 38篇 |
1999年 | 17篇 |
1998年 | 16篇 |
1997年 | 11篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 7篇 |
1993年 | 7篇 |
1992年 | 19篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 12篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 7篇 |
1984年 | 9篇 |
1983年 | 5篇 |
1982年 | 8篇 |
1981年 | 10篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1975年 | 5篇 |
1974年 | 4篇 |
1968年 | 3篇 |
1967年 | 4篇 |
排序方式: 共有3625条查询结果,搜索用时 0 毫秒
1.
2.
Fire and restoration of the largest urban forest of the world in Rio de Janeiro City,Brazil 总被引:1,自引:1,他引:0
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
3.
Two habituation experiments were conducted to investigate how 4‐month‐old infants perceive partly occluded shapes. In the first experiment, we presented a simple, partly occluded shape to the infants until habituation was reached. Then we showed either a probable completion (one that would be predicted on the basis of both local and global cues) or an improbable completion. Longer looking times were found for the improbably completed shape (compared to probable and control conditions), suggesting that the probable shape was perceived during partial occlusion. In the second experiment, infants were habituated to more ambiguous partly occluded shapes, where local and global cues would result in different completions. For adults, the percept of these shapes is usually dominated by global influences. However, after habituation the infants looked longer at the globally completed shapes. These results suggest that by the age of 4 months, infants are able to infer the perceptual completion of partly occluded shapes, but for more ambiguous shapes, this completion seems to be dominated by local influences. 相似文献
4.
Leontine van de Ven Marcel Post Luc de Witte Wim van den Heuvel 《Disability & Society》2005,20(3):311-329
The concept of integration is not well defined. It not known how people with disabilities experience integration. In this study qualitative methods were used. The aim of the article is to define a model of successful integration based on the perspectives of people with disabilities and people within their social environment. Integration consists of five elements: functioning ordinarily without receiving special attention, mixing with others that are not disabled, taking part in society, trying to realize one’s potential and directing one’s own life. Integration is obtained through a process of interaction between a person with a disability and society. This process is influenced by personal, societal and support factors. The individual with a disability and society have a mutual responsibility with respect to integration. 相似文献
5.
Trends in online media relations: Web-based corporate press rooms in leading international companies
An analysis of 120 corporate websites from Denmark, France, Germany, Norway, Singapore, Spain, the United Kingdom and the United States reveals, for the first time, international results about the implementation and use of virtual press rooms. This article shows the importance that large international companies attribute to Web-based media centers to achieve organizational objectives and to meet journalists’ demands for information and audiovisual resources. The study also shows, however, that most press rooms are far from being complete, efficient, easy-to-use, reliable and updated on a daily basis. In fact, there is not a single country from those analyzed that consistently stands out from the rest. In most of them, good results in certain areas coexist with significant shortcomings in others, resulting in some cases in poor press rooms that may not achieve the desired public relations objectives. 相似文献
6.
7.
Máire Ní Bhrolcháin 《Revue europeenne de demographie》1992,8(1):23-45
The paper shows that (a) the age difference between spouses can be and has been different for men and women; (b) male and female age differences can exhibit different trends; (c) the discrepancy is due to remarriage; (d) the age difference fluctuates substantially through time; (e) trends in the age difference are not readily interpretable as reflecting change in the relative status of the sexes; and (f) that trends in the age difference may be linked to marriage market conditions. The paper argues that marriage and fertility data for both men and women are increasingly necessary because of rises in marital breakdown and the associated divergence of the experience of men and women.Cet article montre que (a) les différences d'âge entre époux peuvent être et ont été dissemblables pour les hommes et les femmes; (b) les différences d'âge masculines et féminines peuvent présenter des tendances différentes; (c) la divergence est due aux remariages; (d) les différences d'âge varient de façon importante au cours du temps; (e) les tendances dans les différences d'âge ne sont pas simplement interprétables en termes de changements dans le statut relatif des sexes; et (f) les tendances dans les différences d'âge peuvent être reliées aux conditions du marché matrimonial. L'article montre que les données sur le mariage et la fécondité à la fois des hommes et des femmes, sont de plus en plus nécessaires du fait de l'accroissement des ruptures d'unions et de la divergence des expériences masculines et féminines, qui lui est associée.
An earlier version of this paper, His and her age gap: asymmetry in the age difference between partners, was a contributed paper to Session F27 of the General Conference of the International Union for the Scientific Study of Population, New Delhi, 20–27 September 1989. A longer version appeared as LS Working Paper 70, issued by City University Social Statistics Research Unit, September 1990. 相似文献
An earlier version of this paper, His and her age gap: asymmetry in the age difference between partners, was a contributed paper to Session F27 of the General Conference of the International Union for the Scientific Study of Population, New Delhi, 20–27 September 1989. A longer version appeared as LS Working Paper 70, issued by City University Social Statistics Research Unit, September 1990. 相似文献
8.
Social Indicators Research - 相似文献
9.
10.
The accuracy of a binary diagnostic test is usually measured in terms of its sensitivity and its specificity, or through positive and negative predictive values. Another way to describe the validity of a binary diagnostic test is the risk of error and the kappa coefficient of the risk of error. The risk of error is the average loss that is caused when incorrectly classifying a non-diseased or a diseased patient, and the kappa coefficient of the risk of error is a measure of the agreement between the diagnostic test and the gold standard. In the presence of partial verification of the disease, the disease status of some patients is unknown, and therefore the evaluation of a diagnostic test cannot be carried out through the traditional method. In this paper, we have deduced the maximum likelihood estimators and variances of the risk of error and of the kappa coefficient of the risk of error in the presence of partial verification of the disease. Simulation experiments have been carried out to study the effect of the verification probabilities on the coverage of the confidence interval of the kappa coefficient. 相似文献