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   961篇
  免费   41篇
  国内免费   22篇
耳鼻咽喉   1篇
儿科学   61篇
妇产科学   8篇
基础医学   87篇
口腔科学   11篇
临床医学   58篇
内科学   205篇
皮肤病学   2篇
神经病学   11篇
特种医学   314篇
外科学   46篇
综合类   12篇
预防医学   25篇
眼科学   3篇
药学   56篇
中国医学   1篇
肿瘤学   123篇
  2023年   4篇
  2022年   2篇
  2021年   10篇
  2020年   3篇
  2019年   5篇
  2018年   10篇
  2017年   4篇
  2016年   7篇
  2015年   11篇
  2014年   18篇
  2013年   20篇
  2012年   21篇
  2011年   17篇
  2010年   15篇
  2009年   21篇
  2008年   15篇
  2007年   25篇
  2006年   12篇
  2005年   17篇
  2004年   11篇
  2003年   10篇
  2002年   17篇
  2001年   19篇
  2000年   10篇
  1999年   27篇
  1998年   48篇
  1997年   41篇
  1996年   62篇
  1995年   46篇
  1994年   34篇
  1993年   39篇
  1992年   11篇
  1991年   12篇
  1990年   15篇
  1989年   35篇
  1988年   40篇
  1987年   35篇
  1986年   30篇
  1985年   41篇
  1984年   21篇
  1983年   23篇
  1982年   28篇
  1981年   24篇
  1980年   13篇
  1979年   8篇
  1978年   11篇
  1977年   30篇
  1976年   22篇
  1975年   17篇
  1969年   2篇
排序方式: 共有1024条查询结果,搜索用时 15 毫秒
1.
Abstract: It has been hypothesized that pineal structure and function might differ between temperate zone and tropical species of mammals because of lower amplitudes of seasonal change in photoperiod and, in some areas, less seasonal climatic variation. Anoura geoffroyi produce a single offspring in November or December of each year on the Caribbean island of Trinidad, at 10°N latitude in the deep tropics. Previous work has shown that this population lacks reproductive responses to photoperiod, and must be enforcing seasonal breeding using a non-photoperiodic cue. Anoura geoffroyi have a minute, thin, and rod-like pineal gland. Throughout much of its length, the pineal courses irregularly within the ventrolateral wall of the great cerebral vein. This intimate relationship may have functional implications. Despite having a very small pineal gland, this species produced a nocturnal rise in serum melatonin. Serum melatonin levels in most individuals were below or near undetectable levels during the light period and rose to a peak averaging 100 pg/ml in the last third of the dark period. Our results indicate that, although the pineal gland of A. geoffroyi is extremely small, serum melatonin levels are comparable to those of other mammals.  相似文献   
2.
3.
4.
Terminal complement complex (TCC) and anaphylatoxin formation in 18 patients with sepsis and 20 patients with acute limb ischemia were studied before the start of treatment and seven days later. The septic or ischemic patients had elevated levels of plasma TCC before start of therapy. In successfully treated patients these concentrations were within the normal range one week later. Similarly, the plasma anaphylatoxin level was increased before therapy and returned to the normal range within seven days. Escherichia coli incubated in vitro in fresh human serum at body temperature started formation of TCC in a dose-related manner. As complement will induce cellular lysis via TCC and edema via anaphylatoxins, anemia and impaired respiration in these patients may be influenced by increased concentrations of terminal complement complexes and of C3a and C5a.  相似文献   
5.
6.
7.
OBJECTIVE: The aim was to establish the potential efficacy, tolerabilityand side-effect profile of electromagnetic therapy as an adjunctto conventional dressings in the treatment of venous leg ulcers. METHOD: A prospective, randomized, double blind controlled clinicaltrial was carried out in a dedicated leg ulcer clinic basedin one urban general practice. Nineteen patients with leg ulcersof confirmed venous aetiology were assessed. The main outcomemeasures were rate and scale of venous leg ulcer healing, changesin patient-reported pain levels, quality of life, degree ofmobility, side effect profile and acceptability to patientsand staff. RESULTS: Sixty-eight per cent of patients attending this dedicated clinicachieved improvements in the size of their ulcer (4, 21%, healedfully) and in reduced pain levels (P < 0.05) during the trial,despite the chronicity of ulcer histories. Patients treatedwith electromagnetic therapy at 800 Hz were found at day 50to have significantly greater healing (P < 0.05) and paincontrol (P < 0.05) than placebo therapy or treatment with600 Hz. All patients reported improved mobility at the end ofthe study. The electromagnetic therapy was well tolerated bypatients, with no differences between groups in reporting adverseevents, and proved acceptable to staff. CONCLUSION: Despite the small numbers in this pilot study, electromagnetictherapy provided significant gains in the healing of venousleg ulcers and reduction in pain. Keywords. Electromagnetic therapy, RCT, leg ulcers, primary care.  相似文献   
8.
Bile duct calculi in patients with primary sclerosing cholangitis   总被引:1,自引:0,他引:1  
  相似文献   
9.
10.
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