全文获取类型
收费全文 | 7958篇 |
免费 | 485篇 |
国内免费 | 53篇 |
专业分类
耳鼻咽喉 | 61篇 |
儿科学 | 104篇 |
妇产科学 | 66篇 |
基础医学 | 1149篇 |
口腔科学 | 128篇 |
临床医学 | 843篇 |
内科学 | 1821篇 |
皮肤病学 | 157篇 |
神经病学 | 870篇 |
特种医学 | 373篇 |
外科学 | 1007篇 |
综合类 | 35篇 |
一般理论 | 14篇 |
预防医学 | 600篇 |
眼科学 | 97篇 |
药学 | 635篇 |
中国医学 | 33篇 |
肿瘤学 | 503篇 |
出版年
2023年 | 42篇 |
2022年 | 82篇 |
2021年 | 211篇 |
2020年 | 131篇 |
2019年 | 183篇 |
2018年 | 206篇 |
2017年 | 152篇 |
2016年 | 184篇 |
2015年 | 230篇 |
2014年 | 312篇 |
2013年 | 406篇 |
2012年 | 645篇 |
2011年 | 645篇 |
2010年 | 373篇 |
2009年 | 351篇 |
2008年 | 589篇 |
2007年 | 610篇 |
2006年 | 542篇 |
2005年 | 506篇 |
2004年 | 446篇 |
2003年 | 371篇 |
2002年 | 353篇 |
2001年 | 56篇 |
2000年 | 50篇 |
1999年 | 58篇 |
1998年 | 84篇 |
1997年 | 63篇 |
1996年 | 47篇 |
1995年 | 47篇 |
1994年 | 25篇 |
1993年 | 37篇 |
1992年 | 25篇 |
1991年 | 18篇 |
1990年 | 28篇 |
1989年 | 24篇 |
1988年 | 16篇 |
1987年 | 27篇 |
1986年 | 27篇 |
1985年 | 16篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 22篇 |
1981年 | 20篇 |
1980年 | 18篇 |
1978年 | 15篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1973年 | 13篇 |
1971年 | 10篇 |
1963年 | 8篇 |
排序方式: 共有8496条查询结果,搜索用时 15 毫秒
101.
Maria C. Haagsma Marcel E. Pieterse Oscar Peters Daniel L. King 《International journal of mental health and addiction》2013,11(4):441-452
This study focuses on the role of gaming expectancies, motives and the experiences of gamers in the development of video game behavior, from normal to problematic behavior. Qualitative interviews were conducted among 21 male gamers between 17 and 28 years of age, to get more of an insight into their excessive gaming patterns. Participants were recruited in several ways such as by distributing flyers and posting messages on gaming websites. Participants were included if they were between 14 and 26 years of age and if they had experienced game related behavior problems at the time of the study or in the past. Two processes emerged from the results that seem to contribute to the transition to an excessive gaming pattern. First, the duration of each single game session may become longer. Second, a game session may be started up more and more frequently. Gamers have several motives and expectancies that play a role in this process of increasing gaming time. Is seems that a combination of these gaming motives can lead to an increase in gaming time. Especially online role playing games were related to excessive gaming and the social mechanisms in these games seem to work as an intensifier for other motives. 相似文献
102.
103.
Validation of a Frailty Index from The Older Persons and Informal Caregivers Survey Minimum Data Set
Jennifer E. Lutomski MS Maria A.E. Baars PhD Janneke A. van Kempen MD Bianca M. Buurman PhD Wendy P.J. den Elzen PhD Aaltje P.D. Jansen PhD Gertrudis I.J.M. Kempen PhD Paul F.M. Krabbe PhD Bas Steunenberg PhD Ewout W. Steyerberg PhD Marcel G.M. Olde‐Rikkert PhD René J.F. Melis PhD 《Journal of the American Geriatrics Society》2013,61(9):1625-1627
104.
105.
Marcel Best Andrew N. Gifford Sung Won Kim Ben Babst Markus Piel Frank Rösch Joanna S. Fowler 《Journal of labelled compounds & radiopharmaceuticals》2012,55(1):39-43
A recent report that the aliphatic dicarboxylic acid, azelaic acid (1,9‐nonanedioic acid) but not related acids, suberic acid (1,8‐octanedioic acid) or sebacic (1,10‐decanedioic acid) acid induces systemic acquired resistance to invading pathogens in plants stimulated the development of a rapid method for labeling these dicarboxylic acids with 11C and 14C for in vivo mechanistic studies in whole plants. 11C‐labeling was performed by reaction of ammonium [11C]cyanide with the corresponding bromonitrile precursor followed by hydrolysis with aqueous sodium hydroxide solution. Total synthesis time was 60 min. Median decay‐corrected radiochemical yield for [11C]azelaic acid was 40% relative to trapped [11C]cyanide, and specific activity was 15 GBq/µmol. Yields for [11C]suberic and sebacic acids were similar. The 14C‐labeled version of azelaic acid was prepared from potassium [14C]cyanide in 45% overall radiochemical yield. Radiolabeling procedures were verified using 13C‐labeling coupled with 13C‐NMR and liquid chromatography–mass spectrometry analysis. The 11C and 14C‐labeled azelaic acid and related dicarboxylic acids are expected to be of value in understanding the mode‐of‐action, transport, and fate of this putative signaling molecule in plants. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
106.
Kimberly A. Babson Matthew Tyler Boden Alex H. Harris Timothy R. Stickle Marcel O. Bonn-Miller 《Journal of substance abuse treatment》2013
Treatments for cannabis dependence are associated with high rates of lapse/relapse, underscoring the importance of identifying malleable risk factors that are associated with quit failure. Whereas research has demonstrated that poor sleep quality following cannabis discontinuation is related to subsequent use, there has yet to be an examination of whether poor sleep quality prior to a quit attempt results in a similar pattern of lapse. The present study addressed this gap by examining the role of pre-quit sleep quality on early lapse to cannabis use following a self-guided quit attempt, among 55 cannabis dependent military veterans. Results indicated that participants who experienced poor pre-quit sleep quality had greater risk for lapse within the first 2 days (out of 7) following their quit attempt. Findings are discussed in terms of improving treatments for individuals who report poor sleep quality prior to a cannabis quit attempt. 相似文献
107.
A systematic review of the survival and complication rates of resin‐bonded fixed dental prostheses after a mean observation period of at least 5 years
下载免费PDF全文
![点击此处可从《Clinical oral implants research》网站下载免费的PDF全文](/ch/ext_images/free.gif)
108.
109.
110.
Accuracy of an automated transthoracic echocardiographic tool for 3D assessment of left heart chamber volumes
下载免费PDF全文
![点击此处可从《Echocardiography (Mount Kisco, N.Y.)》网站下载免费的PDF全文](/ch/ext_images/free.gif)