首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2895篇
  免费   172篇
  国内免费   3篇
耳鼻咽喉   51篇
儿科学   109篇
妇产科学   75篇
基础医学   431篇
口腔科学   32篇
临床医学   219篇
内科学   510篇
皮肤病学   66篇
神经病学   93篇
特种医学   41篇
外科学   252篇
综合类   200篇
一般理论   4篇
预防医学   193篇
眼科学   384篇
药学   182篇
中国医学   15篇
肿瘤学   213篇
  2023年   17篇
  2022年   46篇
  2021年   106篇
  2020年   72篇
  2019年   56篇
  2018年   74篇
  2017年   40篇
  2016年   66篇
  2015年   87篇
  2014年   119篇
  2013年   156篇
  2012年   198篇
  2011年   200篇
  2010年   135篇
  2009年   77篇
  2008年   165篇
  2007年   158篇
  2006年   122篇
  2005年   117篇
  2004年   127篇
  2003年   126篇
  2002年   115篇
  2001年   82篇
  2000年   100篇
  1999年   70篇
  1998年   30篇
  1997年   17篇
  1996年   17篇
  1995年   17篇
  1994年   18篇
  1993年   10篇
  1992年   24篇
  1991年   31篇
  1990年   30篇
  1989年   18篇
  1988年   21篇
  1987年   16篇
  1986年   13篇
  1985年   14篇
  1984年   10篇
  1981年   7篇
  1978年   8篇
  1977年   9篇
  1976年   9篇
  1975年   10篇
  1973年   10篇
  1972年   9篇
  1970年   7篇
  1968年   11篇
  1967年   7篇
排序方式: 共有3070条查询结果,搜索用时 296 毫秒
61.
62.
The present study was undertaken to investigate the food–drug interaction of carbamazepine (CBZ). Common fruit juices [grapefruit juice (GFJ), lime juice (LJ)], known to inhibit the enzyme cytochrome P450 3A4 (CYP3A4), and some widely consumed beverages [milk (M), black tea (BT)] were involved in this study in the presence of CBZ, as might happen during clinical therapy. The effects of the beverages on the pharmacokinetics and drug-induced toxicity of CBZ was observed after concomitant administration for a period of 28 days. Accordingly, the influence of altered bioavailability of CBZ on its antiepileptic activity was investigated. A significant shift in the Cmax as well as Tmax of CBZ was observed in the presence of LJ and GFJ. This increase in bioavailability significantly enhanced hepatotoxicity and delayed the onset of tremor and piloerection against pentylene tetrazole (PTZ)-induced seizure in experimental animals. However, increased toxicity of CBZ was found to be absent with BT. Thus, from our observation, LJ or GFJ in the presence of CBZ significantly increased the bioavailability of CBZ, which might lead to increased toxicity and antiepileptic activity of the drug.  相似文献   
63.
Understanding the conductivity variations induced by compositional changes in sodium super ionic conducting (NASICON) glass materials is highly relevant for applications such as solid electrolytes for sodium (Na) ion batteries. In the research reported in this paper, NASICON-based NCAP glass (Na2.8Ca0.1Al2P3O12) was selected as the parent glass. The present study demonstrates the changes in the Na+ ion conductivity of NCAP bulk glass with the substitution of boron (NCABP: Na2.8Ca0.1Al2B0.5P2.7O12) and gallium (NCAGP: Na2.8Ca0.1Al2Ga0.5P2.7O12) for phosphorus and the resulting structural variations found in the glass network. For a detailed structural analysis of NCAP, NCABP and NCAGP glasses, micro-Raman and magic angle spinning-nuclear magnetic resonance (MAS-NMR) spectroscopic techniques (for 31P, 27Al, 23Na, 11B and 71Ga nuclei) were used. The Raman spectrum revealed that the NCAP glass structure is more analogous to the AlPO4 mesoporous glass structure. The 31P MAS-NMR spectrum illustrated that the NCAP glass structure consists of a high concentration of Q0 (3Al) units, followed by Q0 (2Al) units. The 27Al MAS-NMR spectrum indicates that alumina exists at five different sites, which include AlO4 units surrounded by AlO6 units, Al(OP)4, Al(OP)5, Al(OAl)6 and Al(OP)6, in the NCAP glass structure. The 31P, 27Al and 11B MAS-NMR spectra of the NCABP glass revealed the absence of B–O–Al linkages and the presence of B3–O–B4–O–P4 linkages which further leads to the formation of borate and borophosphate domains. The 71Ga MAS-NMR spectrum suggests that gallium cations in the NCAGP glass compete with the alumina cations and occupy four (GaO4), five (GaO5) and six (GaO6) coordinated sites. The Raman spectrum of NCAGP glass indicates that sodium cations have also been substituted by gallium cations in the NCAP glass structure. From impedance analysis, the dc conductivity of the NCAP glass (∼3.13 × 10−8 S cm−1) is slightly decreased with the substitution of gallium (∼2.27 × 10−8 S cm−1) but considerably decreased with the substitution of boron (∼1.46 × 10−8 S cm−1). The variation in the conductivity values are described based on the structural changes of NCAP glass with the substitution of gallium and boron.

Understanding the conductivity variations induced by compositional changes in sodium super ionic conducting (NASICON) glass materials is highly relevant for applications such as solid electrolytes for sodium (Na) ion batteries.  相似文献   
64.
The elderly, women, and minorities are all less likely to be enrolled in randomized clinical trials (RCTs). Whether differential patient interest in RCTs contributes to these disparities is unclear. The authors surveyed 660 patients' willingness to consider two potential cardiac RCTs of medical therapy vs. percutaneous coronary angioplasty or coronary artery bypass surgery, respectively. The cohort's mean age was 67 years (43% aged ≥70 years; 35% women; and 28% nonwhite). Compared with younger patients, those aged ≥70 years were equal or more likely to consider both the percutaneous coronary angioplasty (46% vs. 41%) and coronary artery bypass surgery RCTs (35% vs. 31%). Race also had no significant impact on trial enrollment, yet women were significantly less likely than men to participate in either RCT. In conclusion, patient willingness to consider RCT participation does not explain underenrollment of elderly and minority patients. Women, however, were more reluctant to consider RCTs, an area requiring further study.  相似文献   
65.
66.
67.
Mycotic aneurysms, especially outside the aorta, are uncommon, with group A Streptococcus a particularly rare cause. We report a case of extra-aortic mycotic aneurysm following a sore throat without demonstrable bacteremia where identification of the pathological organism was made by molecular diagnostic techniques after a standard laboratory culture was negative.  相似文献   
68.
69.
70.
Journal of Digital Imaging - Cardiovascular diseases (CVDs) are the top ten leading causes of death worldwide. Atherosclerosis disease in the arteries is the main cause of the CVD, leading to...  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号