全文获取类型
收费全文 | 437篇 |
免费 | 19篇 |
国内免费 | 3篇 |
专业分类
耳鼻咽喉 | 4篇 |
儿科学 | 40篇 |
妇产科学 | 10篇 |
基础医学 | 25篇 |
口腔科学 | 2篇 |
临床医学 | 36篇 |
内科学 | 87篇 |
皮肤病学 | 5篇 |
神经病学 | 26篇 |
特种医学 | 18篇 |
外科学 | 67篇 |
综合类 | 7篇 |
一般理论 | 1篇 |
预防医学 | 27篇 |
眼科学 | 58篇 |
药学 | 17篇 |
中国医学 | 1篇 |
肿瘤学 | 28篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 11篇 |
2021年 | 21篇 |
2020年 | 10篇 |
2019年 | 22篇 |
2018年 | 14篇 |
2017年 | 12篇 |
2016年 | 17篇 |
2015年 | 8篇 |
2014年 | 22篇 |
2013年 | 26篇 |
2012年 | 39篇 |
2011年 | 33篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 11篇 |
2007年 | 25篇 |
2006年 | 21篇 |
2005年 | 20篇 |
2004年 | 12篇 |
2003年 | 17篇 |
2002年 | 28篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 9篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1995年 | 3篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1989年 | 2篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1985年 | 1篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1971年 | 4篇 |
1970年 | 1篇 |
1956年 | 1篇 |
排序方式: 共有459条查询结果,搜索用时 0 毫秒
1.
2.
Maneet Singh Hennaav Kaur Dhillon Parul Ichhpujani Sudarshan Iyengar Rishemjit Kaur 《Indian journal of ophthalmology》2022,70(5):1773
Purpose:COVID-19-associated mucormycosis (CAM) was a serious public health problem during the second wave of COVID-19 in India. We planned to analyze public perceptions by sentiment analysis of Twitter data regarding CAM.Methods:In this observational study, the application programming interface (API) provided by the Twitter platform was used for extracting real-time conversations by using keywords related to mucormycosis (colloquially known as “black fungus”), from May 3 to August 29, 2021. Lexicon-based sentiment analysis of the tweets was done using the Vader sentiment analysis tool. To identify the overall sentiment of a user on any given topic, an algorithm to label a user “k” based on their sentiments was used.Results:A total of 4,01,037 tweets were collected between May 3 and August 29, 2021, and the peak frequency of 1,60,000 tweets was observed from May 17 to May 23, 2021. Positive sentiment tweets constituted a larger share as compared to negative sentiment tweets, with weekly variations. A temporal analysis of the demand for utilities showed that the demand was high in the initial period but decreased with time, which was associated with the availability of resources.Conclusion:Sentiment analysis using Twitter data revealed that social media platforms are gaining popularity to express one’s emotions during the ongoing COVID-19 pandemic. In our study, time-based assessment of tweets showed a reduction over time in the frequency of negative sentiment tweets. The polarization in the retweet network of users, based on sentiment polarity, showed that the users were well connected, highlighting the fact that such issues bond our society rather than segregating it. 相似文献
3.
4.
5.
6.
Sudarshan Kumar Vijay M.D. D.M. Bhuwan Chandra Tiwari M.D. D.M. Mukul Misra M.D. D.M. Sudhanshu Kumar Dwivedi M.D. D.M. 《Echocardiography (Mount Kisco, N.Y.)》2014,31(1):E24-E26
The mitral valve aneurysm is a rare complication of infective endocarditis involving mitral or aortic valve. The perforation of the mitral valve aneurysm can lead to significant mitral regurgitation (MR) or thromboembolism, which can cause sudden hemodynamic deterioration. We describe here a case of healed infective endocarditis of the aortic valve with ruptured mitral valve aneurysm that led to severe MR. The aneurysm of the anterior mitral leaflet was diagnosed by two‐dimensional transthoracic echocardiography. In this case, three‐dimensional transthoracic echocardiography demonstrated the detailed morphology of mitral valve aneurysm which resulted in successful surgical repair of the aneurysm. 相似文献
7.
8.
Protein kinetics: structures of intermediates and reaction mechanism from time-resolved x-ray data 下载免费PDF全文
Schmidt M Pahl R Srajer V Anderson S Ren Z Ihee H Rajagopal S Moffat K 《Proceedings of the National Academy of Sciences of the United States of America》2004,101(14):4799-4804
We determine the number of authentic reaction intermediates in the later stages of the photocycle of photoactive yellow protein at room temperature, their atomic structures, and a consistent set of chemical kinetic mechanisms, by analysis of a set of time-dependent difference electron density maps spanning the time range from 5 micros to 100 ms. The successful fit of exponentials to right singular vectors derived from a singular value decomposition of the difference maps demonstrates that a chemical kinetic mechanism holds and that structurally distinct intermediates exist. We identify two time-independent difference maps, from which we refine the structures of the corresponding intermediates. We thus demonstrate how structures associated with intermediate states can be extracted from the experimental, time-dependent crystallographic data. Stoichiometric and structural constraints allow the exclusion of one kinetic mechanism proposed for the photocycle but retain other plausible candidate kinetic mechanisms. 相似文献
9.
Senan J. Yasar MD Obai Abdullah MD William Fay MD Sudarshan Balla MD 《Journal of interventional cardiology》2018,31(3):360-367
10.