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   176921篇
  免费   6619篇
  国内免费   397篇
耳鼻咽喉   3075篇
儿科学   6544篇
妇产科学   4508篇
基础医学   24964篇
口腔科学   4876篇
临床医学   13209篇
内科学   32178篇
皮肤病学   5103篇
神经病学   16125篇
特种医学   9296篇
外国民族医学   24篇
外科学   29178篇
综合类   1144篇
一般理论   37篇
预防医学   8311篇
眼科学   4669篇
药学   12278篇
中国医学   353篇
肿瘤学   8065篇
  2021年   1250篇
  2020年   1144篇
  2019年   1317篇
  2018年   2927篇
  2017年   2415篇
  2016年   3361篇
  2015年   3759篇
  2014年   3946篇
  2013年   5501篇
  2012年   8541篇
  2011年   8020篇
  2010年   4747篇
  2009年   3824篇
  2008年   7891篇
  2007年   8802篇
  2006年   8807篇
  2005年   9193篇
  2004年   8774篇
  2003年   8651篇
  2002年   8582篇
  2001年   6431篇
  2000年   6510篇
  1999年   5663篇
  1998年   1716篇
  1997年   1427篇
  1996年   1099篇
  1995年   921篇
  1994年   845篇
  1992年   2504篇
  1991年   2416篇
  1990年   2378篇
  1989年   2242篇
  1988年   1963篇
  1987年   1943篇
  1986年   1811篇
  1985年   1754篇
  1984年   1343篇
  1983年   1083篇
  1979年   1440篇
  1978年   1056篇
  1977年   906篇
  1976年   785篇
  1975年   1130篇
  1974年   1171篇
  1973年   1064篇
  1972年   1083篇
  1971年   1031篇
  1970年   922篇
  1969年   874篇
  1968年   836篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.

Introduction  

Ethanol has a suppressive effect on inflammation and the immune system, but the effect of ethanol on tendon healing in vivo has not been studied. The purpose of this study was to investigate the histological and biomechanical effects of ethanol intake on tendon healing in a rat tendon injury model.  相似文献   
95.
96.
OBJECTIVE: To introduce 1,1,1,2 tetrafluoroethane (TFE), as a new material for cryosurgery of gingival melanin pigmentation (GMP). STUDY DESIGN: Twenty-one patients with GMP were treated using a TFE-cooled cotton swab. Standard digital images of pigmented areas were measured preoperatively and postoperatively with image-analyzing software. The Mann-Whitney U test was used for statistical analysis. RESULTS: Keratinization was completed 3 to 4 weeks after application, without any trace of pigmentation. Statistical analysis revealed a significant difference between preoperative and postoperative measurements of pigmented areas (P < .05). During the follow-up period, no side effects were observed and improved esthetics were maintained up to month 30. CONCLUSIONS: The clinical outcomes of cryosurgery with TFE for treatment of GMP are very satisfactory. The use of TFE for cryosurgical treatment of GMP is practical and inexpensive. Moreover, unlike other cryosurgery methods no special equipment is required, and it is safe to store in the dental clinic.  相似文献   
97.
Liquid-crystalline main-chain polyesters with polystyrene side chains of different length and number per main chain were synthesized using aromatic hydroxyfunctional polystyrene (PS) macromonomers, terephthalic acid derivatives and tert-butylhydroquinone as co-diol. The molecular weight of the polystyrene side chain was varied in the range from 1000 to 20000. The influence of this novel type of substituent on the solubility, thermal behaviour and miscibility with PS as a flexible matrix polymer is discussed. The properties of the new compounds are compared to those of the respective homopolyester. The graft copolyesters are, depending on the characteristics of the polymeric substituent, soluble in common organic solvents and their thermal transition points are lowered compared to the homopolyester. Compared to blends of the homopolyester, the improvement of miscibility of the polymer-substituted rigid rods with PS as an example for a flexible matrix polymer can be valued as a step to molecular reinforcement.  相似文献   
98.
Coronary artery bypass grafts: visualization with MR imaging   总被引:1,自引:0,他引:1  
Gomes  AS; Lois  JF; Drinkwater  DC  Jr; Corday  SR 《Radiology》1987,162(1):175
  相似文献   
99.
K Rehse  U Lükens  G Claus 《Archiv der Pharmazie》1987,320(12):1233-1238
Platelet Aggregation Inhibiting and Anticoagulant Effects of Oligoamines, VII: Benzene-1,3,5-trialkanamines Seventeen title compounds were synthesized. Platelet aggregation induced by collagen in vitro is inhibited by 9 of them at IC50 = 2–4 μmol/L. Seven compounds depress the formation of fibrin to ≦ 25 % of normal in concentrations below 50 μmol/L. Compound 15 [4-(2-thienylbutyl)benzene-1,3,5-trimethanamine is the first oligoamine which shows anticoagulant and antiplatelet effects at the same concentration (25 μmol/L).  相似文献   
100.
In the operative treatment of appendicitis the so called negative appendectomy is an important issue because of its increased morbidity. From the hypothesis that the intestinal diamine oxidase activity is a suitable marker of mucosal integrity, the distribution pattern of the enzyme in appendices histologically classified as inflamed or not inflamed was studied. Histologically apparent inflammation of the appendix was connected with a significant reduction of diamine oxidase activity. The determination of this enzymic activity may be a simple and sensitive test for mucosal inflammation of the appendix even at a very early state. This could reduce the rate of negative appendectomies and influence thereby risk-cost-benefit calculations.  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