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   135779篇
  免费   9638篇
  国内免费   630篇
耳鼻咽喉   1651篇
儿科学   3418篇
妇产科学   2445篇
基础医学   17394篇
口腔科学   2895篇
临床医学   13297篇
内科学   27993篇
皮肤病学   1754篇
神经病学   11957篇
特种医学   5398篇
外科学   21817篇
综合类   1916篇
现状与发展   1篇
一般理论   173篇
预防医学   12400篇
眼科学   2916篇
药学   9603篇
  2篇
中国医学   179篇
肿瘤学   8838篇
  2023年   671篇
  2022年   1046篇
  2021年   2571篇
  2020年   1466篇
  2019年   2395篇
  2018年   2926篇
  2017年   2114篇
  2016年   2230篇
  2015年   2715篇
  2014年   4015篇
  2013年   6057篇
  2012年   8868篇
  2011年   9439篇
  2010年   5253篇
  2009年   4808篇
  2008年   8384篇
  2007年   8985篇
  2006年   8563篇
  2005年   8713篇
  2004年   8373篇
  2003年   7874篇
  2002年   7682篇
  2001年   1277篇
  2000年   1052篇
  1999年   1397篇
  1998年   1627篇
  1997年   1303篇
  1996年   1253篇
  1995年   1216篇
  1994年   1031篇
  1993年   1005篇
  1992年   839篇
  1991年   866篇
  1990年   758篇
  1989年   733篇
  1988年   755篇
  1987年   737篇
  1986年   759篇
  1985年   835篇
  1984年   907篇
  1983年   867篇
  1982年   1130篇
  1981年   1156篇
  1980年   964篇
  1979年   631篇
  1978年   668篇
  1977年   597篇
  1976年   519篇
  1975年   468篇
  1974年   471篇
排序方式: 共有10000条查询结果,搜索用时 359 毫秒
151.
152.
153.
The history of appendicitis has been briefly reviewed and a plea made for a renewed interest in this disease on the part of all physicians.A series of one hundred consecutive cases of acute suppurative appendicitis, with two deaths, has been presented. In twenty-five of these the appendix had perforated with one death—a mortality rate of 4.0 per cent. In the seventy-five cases without perforation there was one death—a mortality rate of 1.33 per cent. The mortality rate for the entire series was 2.0 per cent.These attacks occurred for the most part in young and middle aged patients, 70 per cent being less than thirty years old and 80 per cent less than forty.The symptoms as seen in this series have been presented as follows: pain, tenderness, rigidity, vomiting, rapid pulse, fever, leucocytosis, diarrhea and constipation. The constant presence of pain, although not usually severe, and the overwhelming frequency of tenderness and rigidity have been pointed out. Nausea and vomiting in association with abdominal pain have been emphasized as of major significance.The importance of early diagnosis and operation and their relationship to mortality and morbidity has been stressed.The danger of laxatives has been reiterated.Treatment has been discussed with a plea for early operation.The advantages of certain points in technic have been mentioned.A frank statement of the need for more and earlier consultations in suspected appendicitis and a discussion of the responsibilities of both physician and surgeon have been presented.  相似文献   
154.
155.
156.
157.
158.
159.
Several case reports have implicated Ginkgo biloba in clinically adverse bleeding disorders. Ginkgo biloba has been reported to increase pain-free walking distance among patients with peripheral artery disease (PAD). Standard PAD therapy includes 325 mg/day aspirin. The objective of this study was to examine potential adverse effects of concomitant aspirin and Ginkgo biloba on platelet function. Ginkgo biloba (EGb 761, 300 mg/day) was compared with placebo for effects on measures of platelet aggregation among adults consuming 325 mg/day aspirin in a randomized, double-blind, placebo-controlled, parallel design trial of 4-week duration. Participants were adults, age 69 +/- 10 years, with PAD or risk factors for cardiovascular disease. Outcome measures included platelet function analysis (PFA-100 analyzer) using ADP as an agonist (n = 26 placebo; n = 29 ginkgo), and platelet aggregation using ADP, epinephrine, collagen and ristocetin as agonists (n = 21 placebo; n = 23 ginkgo). Participants kept daily logs of bleeding or bruising episodes. There were no clinically or statistically significant differences between treatment groups for any agonists, for either PFA-100 analysis or platelet aggregation. Reports of bleeding or bruising were infrequent and similar for both study groups. In conclusion, in older adults with PAD or cardiovascular disease risk, a relatively high dose of Ginkgo biloba combined with 325 mg/day daily aspirin did not have a clinically or statistically detectable impact on indices of coagulation examined over 4 weeks, compared with the effect of aspirin alone. No adverse bleeding events were observed, although the trial was limited to a small sample size.  相似文献   
160.
BACKGROUND: Studies have shown that alcoholics have smaller brain volumes than non-alcoholic cohorts, but an effect of family history (FH) of heavy drinking on brain volume has not been demonstrated. We examined the relationship between an FH of heavy drinking and both brain shrinkage as measured by the ratio of brain volumes to intracranial volume (ICV) as well as maximal brain growth as measured by ICV in early-onset and late-onset alcoholics. METHODS: With T1-weighted resonance imaging, we measured ICV, brain volume, and white and gray matter volume in adult treatment-seeking late-onset and early-onset alcoholics with either a positive or a negative FH of heavy alcohol use, and in healthy control subjects. We also calculated brain shrinkage using a ratio of soft tissue volumes to ICV. RESULTS: The FH positive alcoholic patients had significantly smaller ICVs than FH negative patients, suggesting smaller premorbid brain growth. Brain shrinkage did not correlate with FH. Late-onset alcoholics showed a greater difference in ICV between FH positive and FH negative patients than early-onset alcoholics. Late-onset FH positive patients also had significantly lower IQ scores than late-onset FH negative patients, and IQ scores were correlated with ICV. CONCLUSIONS: These data provide evidence that parental alcohol use might increase risk for alcoholism in offspring in part by a genetic and/or environmental effect that might be related to reduced brain growth.  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