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   36027篇
  免费   2026篇
  国内免费   106篇
耳鼻咽喉   442篇
儿科学   2148篇
妇产科学   707篇
基础医学   4613篇
口腔科学   817篇
临床医学   2541篇
内科学   7332篇
皮肤病学   839篇
神经病学   1907篇
特种医学   801篇
外科学   4999篇
综合类   1327篇
一般理论   15篇
预防医学   2118篇
眼科学   1544篇
药学   3512篇
中国医学   275篇
肿瘤学   2222篇
  2023年   237篇
  2022年   670篇
  2021年   1164篇
  2020年   639篇
  2019年   865篇
  2018年   1050篇
  2017年   729篇
  2016年   956篇
  2015年   999篇
  2014年   1358篇
  2013年   1759篇
  2012年   2420篇
  2011年   2443篇
  2010年   1385篇
  2009年   1242篇
  2008年   1783篇
  2007年   1757篇
  2006年   1773篇
  2005年   1390篇
  2004年   1395篇
  2003年   1188篇
  2002年   1014篇
  2001年   825篇
  2000年   868篇
  1999年   732篇
  1998年   310篇
  1997年   214篇
  1996年   224篇
  1995年   219篇
  1994年   176篇
  1993年   153篇
  1992年   500篇
  1991年   406篇
  1990年   432篇
  1989年   397篇
  1988年   357篇
  1987年   356篇
  1986年   348篇
  1985年   323篇
  1984年   264篇
  1983年   220篇
  1982年   140篇
  1979年   230篇
  1978年   148篇
  1977年   180篇
  1975年   171篇
  1974年   182篇
  1973年   182篇
  1972年   173篇
  1971年   161篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Buprenorphine was introduced as a potent analgesic with low abuse potential. Reports of buprenorphine abuse by opiate abusers have accumulated over the years, highlighting its use as a cheap alternative to heroin. The lower potency compared with heroin is being compensated by using a cocktail of buprenorphine with benzodiazepines or cyclizine. This study of 18 cases seen over 3 years broadly confirms these findings. Four cases reported haematemesis during acute withdrawal, a symptom not reported in earlier studies.  相似文献   
92.
Objective: To determine if drip infusion should be discontinued after full recovery of the patient from anaesthesia after minilaparotomy cholecystectomy in uncomplicated cases.Design: A randomised controlled clinical trial on 60 patients, from the waiting list, of cholelithiasis/cholecystitis operated by minilaparotomy cholecystectomy between November 1995 to March 1996. 30 patients did not receive postoperative IV drip infusion and in 30 patients 12–24 hours of standard drip transfusion was continued according to the current practice.Setting: Single Surgical Unit, SS Hospital, Banaras Hindu University, Varanasi, India.Main outcome measure: Recognition of clinical indication for continuation of. IV drip infusion after full recovery from anaesthesia.Results: In the cohorts of 30 patients each who were or were not given IV drip infusion after full recovery from anaesthesia following minilaparotomy cholecystectomy the observations on pulse rate, blood pressure, time to first voiding of urine and time to start first oral intake of fluids were identical. However postoperative urinary retention occured in 6 (20%) patients in whom the IV drip infusion was given.Conclusion: There is no clinical indication to continue IV drip infusion after full recovery from anaesthesia in patients operated for minilaparotomy cholecystectomy.  相似文献   
93.
94.
Serum ceruloplasmin levels were estimated in 81 patients within one week after an attack of acute myocardial infarction. A total of 126 healthy subjects were taken as controls and investigated for this copper containing protein. Results showed that there is an elevation in the levels of serum ceruloplasmin in patients as compared to the controls. Ceruloplasmin levels showed a return to almost normal values in 54 follow-up cases of acute myocardial infarction during the fourth week after infarction.  相似文献   
95.
96.
97.
A prospective randomized controlled study was designed to evaluate differences in efficacy and complication rate between the two most commonly used sclerosing agents, sodium tetradecyl sulfate (STD) and polidocanol. Of 52 patients with esophageal variceal bleeding, 26 were randomized to receive sclerotherapy with 1.5% STD and 26 to receive 1% polidocanol at weekly intervals. Eradication of varices was achieved in 88% patients each of the STD and polidocanol group. There was no significant difference between patients injected with STD and polidocanol with regard to re-bleeding (27% vs. 15%) and mortality (11.5% in both). The use of STD, in contrast to polidocanol, was associated with a higher incidence of complications in terms of severe retrosternal pain (27% vs. 4%), deep ulceration (53% vs. 23%), dysphagia (88% vs. 46%), and stricture formation (27% vs. 8%). It was concluded that these two agents were similar in efficacy. However, polidocanol was superior due to a lower incidence of complications.  相似文献   
98.
Standardization of allergens are achieved by in vitro and in vivo methods. Some of the allergens from Western countries are standardized using biological potency of the extracts but no attempt has been made till now to standardize any of the pollen extracts from India based on biological units. Therefore, we have attempted to standardize two important pollen allergens Ricinus communis and Holoptelea integrifolia by biological methods. Broadly the methods adopted by Dreborg and Grimmer (1983) was followed. Skin prick tests were carried out with the extracts of R. communis and H. integrifolia on 15 allergic patients in five three fold log dilutions starting with 1:10, in 50% glycerinated buffer. Glycerinated buffer (50%) and histamine dihydrochloride (1 mg/ml) were used as negative and positive controls, respectively. The mean wheal diameter obtained with different concentrations showed a gradual systematic fall with increase in dilution. The mean relative diameter (% of histamine reaction) varied from 124.1 +/- 8.9 to 33.7 +/- 6.1 and 78.9 +/- 5.5 to 21.4 +/- 3.8 with the highest and lowest concentrations of R. communis and H. integrifolia pollen antigens, respectively. The histamine equivalent concentration of antigen 1,000 Biological Units (BU) obtained for crude pollen extracts of R. communis and H. integrifolia was 1:17 and 1:22 respectively.  相似文献   
99.
Five new N alpha-(5,8-dideazapteroyl)-L-ornithines have been prepared using multistep synthetic sequences. These include N alpha-[5-(trifluoromethyl)-5,8-dideazapteroyl]-L-ornithine, 3, as well as N alpha-[5-(trifluoromethyl)-5,8-dideazaisopteroyl]-L-ornithine, 4, and its 5-fluoro and 5-chloro analogues. Both of the compounds containing a 5-(trifluoromethyl) group (3 and 4) were found to be excellent inhibitors of homogeneous hog liver folylpolyglutamate synthetase, having Ki values in the same range as N alpha-(5-chloro-5,8-dideazapteroyl)-L-ornithine, 2, (approximately 10 nM). However, the bridge-reversed isomer of 2 was 60-fold less inhibitory than 2.  相似文献   
100.
BACKGROUND: Allergen extracts are unstable, heat labile or susceptible to proteases. Stability of allergen extracts is important for proper diagnosis and therapy of allergic disorders. OBJECTIVE: The present study was undertaken to determine the preservation and stabilization conditions of Imperata cylindrica (Ic) grass pollen extract. METHODS: The Ic extract was kept with 0.1 mepsilon-aminocaproic acid (EACA), 0.75 m sucrose, 5% glycerol, 0.03% human serum albumin (HSA) or 0.4% phenol for different time periods. The extracts were stored for 3, 6 and 12 months each at 4 degrees C, 4 degrees C with daily exposure to room temperature (RT) for 1 h, and RT. The quality of extracts was analysed by SDS-PAGE, Western blot, ELISA, ELISA inhibition and skin test. RESULTS: Extracts kept with EACA and sucrose retained most of the protein bands followed by glycerol as determined by SDS-PAGE and Western blot during all storage periods and conditions in comparison with standard extracts. The extracts kept with HSA, phenol and without preservative (WP) showed protein degradation below 33 kDa after 3 months storage at all conditions. However, a 67-kDa allergen was stable in these extracts. EACA extract required 75 to 120 ng of protein for 50% inhibition in IgE binding under different conditions, whereas standard extract required 70 ng for the same. ELISA also demonstrated high allergenic reactivity of EACA extract. ID test on allergy patients with EACA extract demonstrated same allergenic potency as that of standard extract. CONCLUSION: EACA is the best preservative/stabilizing agent of Ic pollen extract, followed by sucrose and glycerol. Ic extract kept with phenol, HSA and without preservative showed degradation within 3 months. EACA preserved extract is equally potent as that of standard extract up to 1 year's storage.  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