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   1440574篇
  免费   100687篇
  国内免费   1986篇
耳鼻咽喉   19462篇
儿科学   50559篇
妇产科学   37839篇
基础医学   197466篇
口腔科学   35037篇
临床医学   122576篇
内科学   286757篇
皮肤病学   28626篇
神经病学   115825篇
特种医学   59641篇
外国民族医学   660篇
外科学   223474篇
综合类   29284篇
现状与发展   1篇
一般理论   377篇
预防医学   112543篇
眼科学   30491篇
药学   103648篇
  2篇
中国医学   3045篇
肿瘤学   85934篇
  2018年   33879篇
  2017年   26309篇
  2016年   29379篇
  2015年   13195篇
  2014年   17855篇
  2013年   26859篇
  2012年   42494篇
  2011年   57840篇
  2010年   40515篇
  2009年   32685篇
  2008年   54986篇
  2007年   59612篇
  2006年   39909篇
  2005年   40400篇
  2004年   40735篇
  2003年   40509篇
  2002年   38082篇
  2001年   64218篇
  2000年   66861篇
  1999年   56545篇
  1998年   15303篇
  1997年   13936篇
  1996年   14257篇
  1995年   13540篇
  1994年   12850篇
  1993年   11834篇
  1992年   44576篇
  1991年   43539篇
  1990年   42327篇
  1989年   40174篇
  1988年   36942篇
  1987年   36269篇
  1986年   33637篇
  1985年   32303篇
  1984年   24151篇
  1983年   20286篇
  1982年   11747篇
  1981年   10691篇
  1980年   9546篇
  1979年   21343篇
  1978年   14829篇
  1977年   12535篇
  1976年   11701篇
  1975年   12628篇
  1974年   14678篇
  1973年   14117篇
  1972年   12944篇
  1971年   11729篇
  1970年   11068篇
  1969年   10041篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
151.
152.
153.
154.
To determine the protective effect of aloe-emodin (AE) from high glucose induced toxicity in RIN-5F (pancreatic β-cell) cell and restoration of its function was analyzed. RIN-5F cells have been cultured in high glucose (25 mM glucose) condition, with and without AE treatment. RIN-5F cells cultured in high glucose decreased cell viability and increased ROS levels after 48 hr compared with standard medium (5.5 mM glucose). Glucotoxicity was confirmed by significantly increased ROS production, increased pro-inflammatory (IFN-γ, IL-1β,) & decreased anti-inflammatory (IL-6&IL-10) cytokine levels, increased DNA fragmentation. In addition, we found increased Bax, caspase 3, Fadd, and Fas and significantly reduced Bcl-2 expression after 48 hr. RIN-5F treated with both high glucose and AE (20 μM) decreased ROS generation and prevent RIN-5F cell from glucotoxicity. In addition, AE treated cells cultured in high glucose were transferred to standard medium, normal responsiveness to glucose was restored within 8hr and normal basal insulin release within 24 hr was achieved when compared to high glucose.  相似文献   
155.
156.
157.
158.

Objectives

Short successive periods of skeletal muscle disuse have been suggested to substantially contribute to the observed loss of skeletal muscle mass over the life span. Hospitalization of older individuals due to acute illness, injury, or major surgery generally results in a mean hospital stay of 5 to 7 days, during which the level of physical activity is strongly reduced. We hypothesized that hospitalization following elective total hip arthroplasty is accompanied by substantial leg muscle atrophy in older men and women.

Design and participants

Twenty-six older patients (75 ± 1 years) undergoing elective total hip arthroplasty participated in this observational study.

Measurements

On hospital admission and on the day of discharge, computed tomographic (CT) scans were performed to assess muscle cross-sectional area (CSA) of both legs. During surgery and on the day of hospital discharge, a skeletal muscle biopsy was taken from the m. vastus lateralis of the operated leg to assess muscle fiber type–specific CSA.

Results

An average of 5.6 ± 0.3 days of hospitalization resulted in a significant decline in quadriceps (?3.4% ± 1.0%) and thigh muscle CSA (?4.2% ± 1.1%) in the nonoperated leg (P < .05). Edema resulted in a 10.3% ± 1.7% increase in leg CSA in the operated leg (P < .05). At hospital admission, muscle fiber CSA was smaller in the type II vs type I fibers (3326 ± 253 μm2 vs 4075 ± 279 μm2, respectively; P < .05). During hospitalization, type I and II muscle fiber CSA tended to increase, likely due to edema in the operated leg (P = .10).

Conclusions

Six days of hospitalization following elective total hip arthroplasty leads to substantial leg muscle atrophy in older patients. Effective intervention strategies are warranted to prevent the loss of muscle mass induced by short periods of muscle disuse during hospitalization.  相似文献   
159.

Objectives

This study aimed to explore the genetic diversity of Streptococcus pneumoniae isolates in a Tunisian pneumology hospital.

Methods

A total of 141 S. pneumoniae strains isolated between 2009–2016 in the microbiology laboratory at A. Mami Hospital of Pneumology were investigated. Antimicrobial susceptibility testing was performed the disk diffusion method. MICs of penicillin G, amoxicillin and cefotaxime were determined by Etest. Serotyping was inferred from the results of multiplex PCR targeting 40 serotypes. Sequence types (STs) were determined by multilocus sequence typing (MLST).

Results

Among the 141 S. pneumoniae isolates, 98 (69.5%) were resistant to erythromycin. Evaluation of β-lactam susceptibility showed that 90 strains (63.8%) were non-susceptible to penicillin, whereas 48 (34.0%) had decreased susceptibility to amoxicillin and 21 (14.9%) to cefotaxime. Twenty-five serotypes were detected, and 10 isolates were classified as non-typeable. Vaccine coverage was 56.7%, 60.3% and 75.2% for pneumococcal conjugate vaccine 7 (PCV7), PCV10 and PCV13, respectively. Overall, 73 STs were identified, including 23 described for the first time. The most frequent STs were ST179 (n?=?17), ST3772 (n?=?14), ST2918 (n?=?10) and ST4003 (n?=?5), related to serotypes 19F, 19A, 14 and 23F, respectively. Moreover, 110 strains were classified within 45 STs. Three international antimicrobial-resistant clones were found, including Denmark14-ST230 (n?=?22), Spain9V-ST156 (n?=?22) and Portugal19F-ST177 (n?=?20).

Conclusion

This study emphasises the clonal and international dissemination of antimicrobial-resistant S. pneumoniae clones. Significant differences in genetic variation were documented by MLST within the various serotypes identified.  相似文献   
160.
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