全文获取类型
收费全文 | 1731篇 |
免费 | 100篇 |
专业分类
管理学 | 162篇 |
民族学 | 21篇 |
人口学 | 252篇 |
理论方法论 | 122篇 |
综合类 | 29篇 |
社会学 | 833篇 |
统计学 | 412篇 |
出版年
2024年 | 4篇 |
2023年 | 35篇 |
2022年 | 24篇 |
2021年 | 39篇 |
2020年 | 90篇 |
2019年 | 112篇 |
2018年 | 145篇 |
2017年 | 156篇 |
2016年 | 139篇 |
2015年 | 71篇 |
2014年 | 117篇 |
2013年 | 348篇 |
2012年 | 140篇 |
2011年 | 50篇 |
2010年 | 44篇 |
2009年 | 35篇 |
2008年 | 42篇 |
2007年 | 31篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 22篇 |
2003年 | 20篇 |
2002年 | 11篇 |
2001年 | 12篇 |
2000年 | 10篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 7篇 |
1996年 | 7篇 |
1995年 | 6篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1987年 | 2篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1982年 | 2篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
1968年 | 2篇 |
1967年 | 1篇 |
排序方式: 共有1831条查询结果,搜索用时 833 毫秒
181.
Plants in cities must cope with various anthropogenic environments that differ from surrounding landscapes. Moreover, the differences in biotic and abiotic conditions among these habitats filter species with suitable traits and niche requirements. Here we aim to identify those attributes that promote species occurrence across and within urban habitat types of large cities. Species composition of spontaneously occurring vascular plant species was recorded in 1-ha plots in seven different urban habitat types in each of 32 European cities. Each species was characterized in terms of dispersal type, growth form, height, seed bank longevity, seed mass, selected leaf traits and ecological indicators including Ellenberg indicator values, Grime’s life strategies, and immigration pathways using information from available species-trait databases. For each species, total frequency of occurrence across all plots and habitat frequency of occurrence across plots of given habitat types were calculated and regression trees were used to relate them to traits and ecological indicators. The most frequently occurring species in the cities tended to be human-dispersed, nutrient-demanding plants that prefer drier to mesic soil conditions. These species do not possess the S-strategy and usually produce seeds of low mass forming short-term persistent seed banks. Habitat-specific responses were also revealed, indicating the effects of between- and within-habitat heterogeneity on trends in species performance in cities. Such patterns can be overlooked when differences in species occurrences in particular urban habitat types are not considered; thus, habitat-specific responses can resolve inconsistencies found when whole urban floras are analysed as a whole. 相似文献
182.
183.
184.
Markéta Bačáková 《Intercultural Education》2011,22(2):163-175
All children in the Czech Republic have the legal right to primary education, regardless of nationality and legal status. This article is based on a study of refugee children and their educational situation. The study reveals that refugee students in the Czech Republic are not benefiting fully from this fundamental right and that their educational future is in jeopardy. The study identified six major barriers to full participation and educational benefits. Finally, a plan of action to overcome barriers is put forward. Key ingredients are effective information transfer among state agencies, non‐governmental organizations, parents, children and schools. 相似文献
185.
186.
This paper studies the topological approach to social choice theory initiated by G. Chichilnisky (1980), extending it to
the case of a continuum of agents. The social choice rules are continuous anonymous maps defined on preference spaces which
respect unanimity. We establish that a social choice rule exists for a continuum of agents if and only if the space of preferences is contractible. We provide also a topological characterization of such
rules as generalized means or mathematical expectations of individual preferences.
Received: 30 November 1994/Accepted: 22 April 1996 相似文献
187.
Erika Rost Jörn Sonnenburg Ralf Hanatschek Karsten Heinz Philippe Barré Radovan Fuchs Adriana Gjonaj Florian Gruber Slobodanka Koprivica Slavi Krušic Peter Mayr Iulia Mihail Husein Panjeta Nikos Sidiropoulos Viktor Stefov Anneliese Stoklaska Sándor Szigeti Jean-Luc Teffo Ivan Videnovic Albena Vutsova Dagmar Simon Hildegard Matthies 《Transition Studies Review》2007,14(2):205-261
188.
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
189.
Cristina Goenechea Permisán José Antonio García Fernández 《Intercultural Education》2007,18(3):207-213
During the last few years, changes in the Spanish educational system have had a far reaching impact. Several factors have been critical: (1) the progressive decentralization of education by the government, now a responsibility of regional governments; (2) the extension of compulsory education to the age of 16; and finally (3) the increase in the number of immigrant students, which has significantly added to the existing cultural diversity. The enrolment of immigrant students in Spanish schools is a relatively recent phenomenon (starting 15 years ago) when compared with other European countries. Madrid is the region in Spain with the largest number of students. As most of these students were born outside of Spain, we cannot yet speak of a second generation. The research described here investigated how the educational system in Madrid confronted the challenge of an increasing number of immigrant students. The institutional response was the Madrid Regional Government’s Compensatory Education Regional Plan. This encompasses several measures, which are described here. After a critical analysis of educational policies pertaining to immigrant pupils, the paper suggests ways of overcoming a purely compensatory approach. Intercultural education plays a key role is such considerations. 相似文献
190.