全文获取类型
收费全文 | 13431篇 |
免费 | 21篇 |
国内免费 | 4篇 |
专业分类
教育 | 10310篇 |
科学研究 | 1390篇 |
各国文化 | 21篇 |
体育 | 499篇 |
综合类 | 12篇 |
文化理论 | 419篇 |
信息传播 | 805篇 |
出版年
2023年 | 5篇 |
2022年 | 31篇 |
2021年 | 45篇 |
2020年 | 56篇 |
2019年 | 96篇 |
2018年 | 2261篇 |
2017年 | 2174篇 |
2016年 | 1638篇 |
2015年 | 167篇 |
2014年 | 183篇 |
2013年 | 394篇 |
2012年 | 283篇 |
2011年 | 743篇 |
2010年 | 889篇 |
2009年 | 469篇 |
2008年 | 680篇 |
2007年 | 1191篇 |
2006年 | 108篇 |
2005年 | 462篇 |
2004年 | 520篇 |
2003年 | 451篇 |
2002年 | 199篇 |
2001年 | 70篇 |
2000年 | 56篇 |
1999年 | 22篇 |
1998年 | 8篇 |
1997年 | 20篇 |
1996年 | 9篇 |
1995年 | 16篇 |
1994年 | 10篇 |
1993年 | 6篇 |
1992年 | 6篇 |
1991年 | 18篇 |
1990年 | 7篇 |
1989年 | 13篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1983年 | 4篇 |
1982年 | 8篇 |
1981年 | 6篇 |
1980年 | 7篇 |
1978年 | 6篇 |
1977年 | 7篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 8篇 |
1973年 | 6篇 |
1967年 | 4篇 |
1966年 | 6篇 |
1963年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
981.
982.
Kitae Sohn 《The Urban Review》2011,43(2):217-234
The hypothesis of acting White has been heatedly debated and influential over the last 20 years or so in explaining the Black–White
test score gap. Recently, economists have joined the debate and started providing new theoretical and empirical analyses of
the phenomenon. This paper critically reviews the arguments that have been advanced to support and refute the hypothesis.
This review particularly covers the analyses in economics because the economic analyses are relatively new and usually neglected
in other disciplines. Also, nationally representative data are emphasized, whenever possible, to improve the generalizability
of the arguments. This review concludes that although the analyses in both non-economics and economics are thought-provoking
and compelling in some respect, a substantial body of empirical evidence is inconsistent with the assumptions of and results
from the analyses. 相似文献
983.
Margaret Mackey 《Children‘s Literature in Education》2011,42(3):181-183
984.
Samiyyah Black Carolina Estrada Mirza Carolina de la Fuente Ashley Orozco Andrew Trabazo Sofia de la Vega 《Journalism Practice》2019,13(1):35-51
This article examines talks given by 12 female media professionals at a Southern US university’s center on women in communication between 2013 and 2015 to identify the influence of hegemonic masculinity in industry speak about women and professionalism in the fields of journalism, advertising, and public relations. This paper applies a feminist critique of discussions about “work–life balance,” “leaning in,” “emotion,” and language about the role of technology and innovation in women’s careers, to argue that inherent in these discussions about media professionalism are traits that perpetuate binary notions of feminine–masculine traits of the workplace. As a whole, these messages fail to account for notions of intersectionality and perpetuate inequality and masculine power for future professionals. 相似文献
985.
986.
Pascual Marqués-Bruna 《Sports Engineering》2011,13(4):195-204
This study examined aerodynamic properties and boundary layer stability in five cambered airfoils operating at the low Reynolds
numbers encountered in motor racing. Numerical modelling was carried out in the flow regime characterised by Reynolds numbers
0.82–1.29 × 106. The design Reynolds number of 3 × 106 was used as a reference. Aerodynamics variables were computed using AeroFoil 2.2 software, which uses the vortex panel method
and integral boundary layer equations. Validation of AeroFoil 2.2 software showed very good agreement between calculated aerodynamic
coefficients and wind tunnel experimental data. Drag polars, lift/drag ratio, pitching moment coefficient, chordwise distributions
(surface velocity ratio, pressure coefficient and boundary layer thickness), stagnation point, and boundary layer transition
and separation were obtained at angles of attack from −4° to 12°. The NASA NLF(1)-0414F airfoil offers versatility for motor
racing with a wide low-drag bucket, low minimum profile drag, high lift/drag ratio, laminar flow up to 0.7 chord, rapid concave
pressure recovery, high resultant pressure coefficient and stall resistance at low Reynolds numbers. The findings have implications
for the design of race car wings. 相似文献
987.
Test procedures and their accuracy in determining critical fall height (CFH) on sporting grounds are paramount to player safety.
The procedure currently adopted for synthetic turf in Australian football [1] consists of four consecutive drops at various drop heights at three test locations on the sample. The quantity and packing
of the infill in third-generation turf and the pooling effect of the rubber particles with consecutive drops suggests that
the current standard protocol may need re-assessment. Therefore, the purpose of this pilot study was to investigate whether
current methods of testing for CFH are appropriate for third-generation synthetic turf or whether an alternative or adapted
method needs to be developed. CFH was measured, using a HISUN Uniaxe-II Impact Tester, on 12 combinations of synthetic turf
samples (four different products with three shock pad options). Three conditions were investigated on each sample; the existing
protocol; an alternative 12 single-drop protocol and four single drops from the CFH determined from the existing protocol.
A significant difference was found for both absolute and percentage difference between the existing and 12 single-drop protocol,
with p = 0.001 and t = 4.33 and p < 0.001 and t = 6.03, respectively. There was also a significant difference between the CFH reached with and without a shock pad for both
the existing protocol and the 12 single-drop protocol. The results of this pilot study demonstrate that differences do occur
with alterations to the existing protocol and highlight the need for a more detailed characterisation of testing methods on
third-generation synthetic turf and the response of surfaces to them. 相似文献
988.
A number of recent studies have measured the extent and timing of segment rotation during the golf swing. A promising technique,
instantaneous screw axis (ISA) theory, could provide a better expression of segment rotation. In Part 1 of this two-part study,
the objectives are to identify the ISA of the pelvis, shoulders and left arm during the downswing, compute segment angular
velocity relative to that segment’s ISA and verify that ISA theory is a valid tool to analyse segment rotation during the
golf swing. Results indicate that for all subjects, at least 71% of marker velocity is a result of rotation about their respective
ISA, when averaging results over the duration of the downswing, confirming that motion is primarily rotational. Furthermore,
ISA position and orientation of each segment approaches, on average, the expected gross axis of rotation, confirming that
motion about the ISA is representative of joint motion. 相似文献
989.
Eduardo N. Borges Moisés G. de Carvalho Renata Galante Marcos André Gonçalves Alberto H.F. Laender 《Information processing & management》2011
Digital libraries of scientific articles contain collections of digital objects that are usually described by bibliographic metadata records. These records can be acquired from different sources and be represented using several metadata standards. These metadata standards may be heterogeneous in both, content and structure. All of this implies that many records may be duplicated in the repository, thus affecting the quality of services, such as searching and browsing. In this article we present an approach that identifies duplicated bibliographic metadata records in an efficient and effective way. We propose similarity functions especially designed for the digital library domain and experimentally evaluate them. Our results show that the proposed functions improve the quality of metadata deduplication up to 188% compared to four different baselines. We also show that our approach achieves statistical equivalent results when compared to a state-of-the-art method for replica identification based on genetic programming, without the burden and cost of any training process. 相似文献
990.
Kannan Vaidyanathan M. P. Narayanan D. M. Vasudevan 《Indian journal of clinical biochemistry : IJCB》2011,26(4):319-325
Organic acidurias are an important class of inherited metabolic disorders arising due to defect in intermediary metabolic
pathways of carbohydrate, amino acids and fatty acid oxidation. This review summarizes the current knowledge about the important
organic acidurias in the Indian population. Specifically, diagnosis and principles of treatment of organic acidurias are covered.
The salient features of common organic acidurias as well as their prevalence in various parts of the world are reviewed in
some detail. 相似文献