全文获取类型
收费全文 | 39014篇 |
免费 | 2746篇 |
国内免费 | 142篇 |
专业分类
耳鼻咽喉 | 257篇 |
儿科学 | 1400篇 |
妇产科学 | 922篇 |
基础医学 | 4475篇 |
口腔科学 | 735篇 |
临床医学 | 4099篇 |
内科学 | 8085篇 |
皮肤病学 | 702篇 |
神经病学 | 3868篇 |
特种医学 | 1274篇 |
外科学 | 6026篇 |
综合类 | 635篇 |
一般理论 | 60篇 |
预防医学 | 3209篇 |
眼科学 | 991篇 |
药学 | 2781篇 |
中国医学 | 41篇 |
肿瘤学 | 2342篇 |
出版年
2023年 | 124篇 |
2021年 | 501篇 |
2020年 | 377篇 |
2019年 | 630篇 |
2018年 | 752篇 |
2017年 | 592篇 |
2016年 | 600篇 |
2015年 | 784篇 |
2014年 | 1118篇 |
2013年 | 1708篇 |
2012年 | 2607篇 |
2011年 | 2813篇 |
2010年 | 1602篇 |
2009年 | 1456篇 |
2008年 | 2586篇 |
2007年 | 2802篇 |
2006年 | 2746篇 |
2005年 | 2838篇 |
2004年 | 2688篇 |
2003年 | 2478篇 |
2002年 | 2479篇 |
2001年 | 364篇 |
2000年 | 223篇 |
1999年 | 344篇 |
1998年 | 531篇 |
1997年 | 381篇 |
1996年 | 319篇 |
1995年 | 336篇 |
1994年 | 294篇 |
1993年 | 296篇 |
1992年 | 241篇 |
1991年 | 211篇 |
1990年 | 200篇 |
1989年 | 196篇 |
1988年 | 182篇 |
1987年 | 149篇 |
1986年 | 184篇 |
1985年 | 181篇 |
1984年 | 276篇 |
1983年 | 229篇 |
1982年 | 292篇 |
1981年 | 269篇 |
1980年 | 268篇 |
1979年 | 144篇 |
1978年 | 139篇 |
1977年 | 141篇 |
1976年 | 119篇 |
1975年 | 98篇 |
1974年 | 120篇 |
1973年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Alan W. Freeman 《The Journal of neuroscience》2021,41(1):89
Motion perception is a vital part of our sensory repertoire in that it contributes to navigation, awareness of moving objects, and communication. Motion sense in carnivores and primates originates with primary visual cortical neurons selective for motion direction. More than 60 years after the discovery of these neurons, there is still no consensus on the mechanism underlying direction selectivity. This paper describes a model of the cat''s visual system in which direction selectivity results from the well-documented orientation selectivity of inhibitory neurons: inhomogeneities in the orientation preference map for inhibitory neurons leads to spatially asymmetric inhibition, and thus to direction selectivity. Stimulation of the model with a drifting grating shows that direction selectivity results from the relative timing of excitatory and inhibitory inputs to a neuron. Using a stationary contrast-reversing grating reveals that the inhibitory input is spatially displaced in the preferred direction relative to the excitatory input, and that this asymmetry leads to the timing difference. More generally, the model yields physiologically realistic estimates of the direction selectivity index, and it reproduces the critical finding with contrast-reversing gratings that response phase advances with grating spatial phase. It is concluded that a model based on intracortical inhibition can account well for the known properties of direction selectivity in carnivores and primates.SIGNIFICANCE STATEMENT Motion perception is vital for navigation, communication, and the awareness of moving objects. Motion sense depends on cortical neurons that are selective for motion direction, and this paper describes a model for the physiological mechanism underlying cortical direction selectivity. The essence of the model is that intracortical inhibition of a direction-selective cell is spatially inhomogeneous and therefore depends on whether a stimulus generates inhibition before or after reaching the cell''s receptive field: the response is weaker in the former than in the latter case. If the model is correct, it will contribute to the understanding of motion processing in carnivores and primates. 相似文献
4.
5.
6.
Randy P. Auerbach Philippe Mortier Ronny Bruffaerts Jordi Alonso Corina Benjet Pim Cuijpers Koen Demyttenaere David D. Ebert Jennifer Greif Green Penelope Hasking Sue Lee Christine Lochner Margaret McLafferty Matthew K. Nock Maria V. Petukhova Stephanie Pinder‐Amaker Anthony J. Rosellini Nancy A. Sampson Gemma Vilagut Alan M. Zaslavsky Ronald C. Kessler 《International journal of methods in psychiatric research》2019,28(2)
7.
Meredith McKean Junna Oba Junsheng Ma Katherine G Roth Wei-Lien Wang Mariana P. Macedo Fernando C.L. Carapeto Lauren E. Haydu Alan E. Siroy Phuong Vo David S. Hong Agda K. Eterovic Keyur Pravinchandra Patel Roland L Bassett Elizabeth A. Grimm Alexander J. Lazar Scott E. Woodman 《The Journal of investigative dermatology》2019,139(3):728-731
8.
9.
10.
Paula M. Frew Raphiel Murden C. Christina Mehta Allison T. Chamberlain Alan R. Hinman Glen Nowak Judith Mendel Ann Aikin Laura A. Randall Allison L. Hargreaves Saad B. Omer Walter A. Orenstein Robert A. Bednarczyk 《Vaccine》2019,37(2):325-332