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   2589748篇
  免费   185281篇
  国内免费   7571篇
耳鼻咽喉   34293篇
儿科学   85241篇
妇产科学   71635篇
基础医学   363820篇
口腔科学   69702篇
临床医学   234875篇
内科学   516059篇
皮肤病学   62467篇
神经病学   213606篇
特种医学   99960篇
外国民族医学   736篇
外科学   386754篇
综合类   50467篇
现状与发展   5篇
一般理论   974篇
预防医学   196439篇
眼科学   56681篇
药学   188144篇
  8篇
中国医学   5332篇
肿瘤学   145402篇
  2021年   20026篇
  2019年   20662篇
  2018年   29334篇
  2017年   22626篇
  2016年   26267篇
  2015年   29538篇
  2014年   40503篇
  2013年   60526篇
  2012年   80325篇
  2011年   84615篇
  2010年   51094篇
  2009年   49212篇
  2008年   79142篇
  2007年   83970篇
  2006年   85670篇
  2005年   81838篇
  2004年   78832篇
  2003年   76172篇
  2002年   73413篇
  2001年   128458篇
  2000年   131388篇
  1999年   110560篇
  1998年   31274篇
  1997年   27943篇
  1996年   28235篇
  1995年   27396篇
  1994年   25085篇
  1993年   23439篇
  1992年   85202篇
  1991年   81597篇
  1990年   78809篇
  1989年   76090篇
  1988年   69492篇
  1987年   68023篇
  1986年   63565篇
  1985年   60533篇
  1984年   44972篇
  1983年   37982篇
  1982年   22480篇
  1981年   20004篇
  1979年   39002篇
  1978年   27473篇
  1977年   23293篇
  1976年   21518篇
  1975年   22833篇
  1974年   26811篇
  1973年   25399篇
  1972年   23755篇
  1971年   21962篇
  1970年   20199篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
The ravelled sleeve of care. Managing the stresses of residency training   总被引:4,自引:0,他引:4  
J M Colford  S J McPhee 《JAMA》1989,261(6):889-893
  相似文献   
993.
A prospective randomized study was carried out on a total of 686 patients who underwent vaginal or abdominal hysterectomy. Of these, 338 were given prophylactic cefotetan (2 g) and 348 piperacillin (2 g). Both drugs were administered as i.v. bolus 30 min before operation. Findings confirm the higher risk of infection with abdominal hysterectomy and the advantages of the long half-life cephalosporin, cefotetan.  相似文献   
994.
Uveal melanoma radiation. 125I brachytherapy versus helium ion irradiation   总被引:4,自引:0,他引:4  
The optimum radiation therapy for uveal melanoma is uncertain. Both helium ion irradiation and 125I brachytherapy have been used to treat this neoplasm. This investigation analyzed the control and complication rates of uveal melanomas treated with helium ions of 125I plaques. In both a retrospective and a prospective dynamically balanced study, the control rates appeared to be similar. There were more posterior segment complications after 125I plaques and more anterior segment complications, including neovascular glaucoma, after helium ion irradiation. The follow-up period is too short to draw definitive conclusions on the radiation complications. Overall, approximately 89% of eyes were retained and less than 4% of treated eyes were removed because of failure to control the tumor.  相似文献   
995.
alpha 1-Antiproteinase is the major inhibitor of proteolytic enzymes, such as elastase, in human plasma. Its elastase-inhibitory capacity can be inactivated by exposure to hydroxyl radicals (.OH) generated either by pulse radiolysis or by an Fe3+-EDTA/H2O2/ascorbic acid system. Inactivation of alpha 1-antiproteinase by radiolytically-generated .OH under anoxic conditions was decreased by adding a range of anti-inflammatory drugs to the reaction mixtures, including the thiol compound penicillamine. However, under conditions favouring formation of oxysulphur radicals, protection by thiols such as penicillamine was much decreased. It is proposed that sulphur-containing radicals resulting from attack of biologically-produced oxidants upon penicillamine in the presence of O2 can themselves inactivate alpha 1-antiproteinase, and that such radicals might contribute to the side-effects produced by penicillamine or gold thiol therapy in rheumatoid arthritis.  相似文献   
996.
St. Jude Medical valve replacement was performed in 1,039 patients; 320 had aortic (AVR), 543 mitral (MVR), and 176 had double valve replacement (DVR). There were 44(4.2%) early deaths. Follow-up extended in 995 patients from 10 to 130 months, with a cumulative period of 2,730 patients-years. The overall survival rates of AVR, MVR, and DVR patients at 10 years were 60.5%, 89.6%, 90.3% respectively. The linearized incidences of valve thrombosis, thromboembolism, anticoagulation-related hemorrhage, prosthetic valve endocarditis, and significant hemolysis were as follows: 0.11%/pt-yr, 1.33%/pt-yr, 0.04%/pt-yr, 0.18%/pt-yr, and 0.11%/pt-yr, respectively. There were no structural failure after 10 years follow-up. Reoperation (explant and re-replacement or suture repair) was required in 10 patients. Seven of them had periprosthetic leakage, 2 had valve thrombosis, and one underwent reoperation because of a technical error. Actuarially over 98% of patients were free of valve-related mortality at 10 years. St. Jude Medical valve is an excellent alternative for use in the surgical treatment of valvular heart disease.  相似文献   
997.
998.
Skin Granulomas due to Mycobacterium gordonae   总被引:2,自引:0,他引:2  
A 38-year-old woman presented with small, ulcerated, red or bluish nodules on the right hand, clinically resembling mycobacterial granulomas; these appeared a few months after a bite by a rat, while the patient was collecting frogs in a pond in the Belgian Ardennes. The histopathologic picture was compatible with a diagnosis of mycobacterial infection and rare acid-fast bacilli could be found. Repeated bacteriologic investigations were performed and these led to the identification of a strain displaying characteristics of Mycobacterium gordonae. The skin condition responded well to rifampicin (300 mg/day) within 6 months.  相似文献   
999.
1000.
R Firth  P Bell  M Marsh  R A Rizza 《Diabetes》1987,36(10):1130-1138
To determine whether therapy with exogenous insulin or sulfonylureas results in a postprandial pattern of carbohydrate metabolism in patients with non-insulin-dependent diabetes mellitus (NIDDM) that resembles that in nondiabetic individuals, we employed a dual-isotope technique combined with forearm catheterization to examine meal disposition in NIDDM patients, before and after 3 mo of therapy with tolazamide and after 3 mo of therapy with exogenous insulin, with a randomized crossover design. Results were compared with those observed in nondiabetic subjects. Although both forms of therapy improved chronic glycemic control (glycosylated hemoglobin concentration went from 9.6 +/- 0.7 to 7.6 +/- 0.5 and 7.1 +/- 0.2%, respectively, P less than .01), exogenous insulin resulted in a lower postprandial glycemic response than tolazamide (P less than .001). Both agents comparably increased (P less than .01) fasting and integrated postprandial insulin concentrations. However, the initial rate of postprandial increase was greater with exogenous insulin (P less than .05). Tolazamide (P less than .05) but not exogenous insulin increased postprandial C-peptide concentrations. However, tolazamide did not improve the deficient early insulin release. Both agents (P less than .05) lowered postabsorptive hepatic glucose release (from 2.8 +/- 0.3 to 2.3 +/- 0.2 mg . kg-1 . min-1), but not to normal rates (1.8 +/- 0.1 mg . kg-1 . min-1).(ABSTRACT TRUNCATED AT 250 WORDS)  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