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   2524篇
  免费   227篇
  国内免费   14篇
耳鼻咽喉   26篇
儿科学   83篇
妇产科学   61篇
基础医学   379篇
口腔科学   65篇
临床医学   277篇
内科学   392篇
皮肤病学   35篇
神经病学   160篇
特种医学   245篇
外科学   321篇
综合类   47篇
一般理论   1篇
预防医学   239篇
眼科学   23篇
药学   213篇
中国医学   6篇
肿瘤学   192篇
  2022年   20篇
  2021年   29篇
  2020年   20篇
  2019年   31篇
  2018年   35篇
  2017年   40篇
  2016年   46篇
  2015年   50篇
  2014年   53篇
  2013年   77篇
  2012年   99篇
  2011年   95篇
  2010年   76篇
  2009年   84篇
  2008年   101篇
  2007年   142篇
  2006年   91篇
  2005年   113篇
  2004年   98篇
  2003年   79篇
  2002年   88篇
  2001年   68篇
  2000年   94篇
  1999年   101篇
  1998年   54篇
  1997年   52篇
  1996年   55篇
  1995年   39篇
  1994年   23篇
  1993年   41篇
  1992年   62篇
  1991年   53篇
  1990年   48篇
  1989年   54篇
  1988年   41篇
  1987年   51篇
  1986年   32篇
  1985年   39篇
  1984年   27篇
  1983年   16篇
  1981年   19篇
  1979年   24篇
  1978年   31篇
  1977年   21篇
  1976年   24篇
  1975年   20篇
  1974年   15篇
  1973年   16篇
  1972年   18篇
  1970年   24篇
排序方式: 共有2765条查询结果,搜索用时 15 毫秒
1.
2.
We have carried out a prospective randomised, single blind clinical trial to investigate the effect of continuous passive motion on range of knee flexion, lack of extension, pain levels and analgesic use after total knee replacement surgery. 85 subjects were randomly allocated to control or study group. All subjects followed the existing rehabilitation protocol, which permits immediate active range of motion exercises and mobilisation with the study group using continuous passive motion for 1 h, twice a day. Outcome measures employed were range of motion, pain assessed on a visual analogue scale and analgesic use according to the WHO ladder. Blinded evaluation was carried out preoperatively, at time of discharge from hospital, 6 weeks, 6 and 12 months postoperation. No significant difference was observed between groups at all time intervals for each outcome variable using Wilcoxon Rank sum tests. The results substantiate previous findings that short duration continuous passive motion following total knee arthroplasty does not influence outcome of range of motion or reported pain.  相似文献   
3.
The anticancer agent temozolomide labeled with 13C (8-Carbamoyl-3-13C-methylimidazo-[5,1-d]-1,2,3,5-tetrazin-4-(3H)-one), was noninvasively detected in subcutaneous RIF-1 tumors by a selective cross polarization 13C NMR method, at a field strength of 9.4T. Pharmacokinetics of the drug, at a dose of 150 mg/kg, were determined for intravenous and intraperitoneal modes of administration (three animals per mode). The half-life of the drug in the tumors was approximately 60 min. The uptake and clearance of the drug, however, varied significantly between individual hosts, for both modes of administration. These results demonstrate the feasibility of obtaining pharmacokinetics of anticancer agents for individual tumors without the need for a label that might modify drug activity (e.g., fluorine). The variability of the in vivo measurements, even within the same tumor model, demonstrates the necessity of directly monitoring the tumor to evaluate drug pharmacokinetics.  相似文献   
4.
5.
6.
Relationship between TISS and ICU cost   总被引:3,自引:0,他引:3  
Objective: To determine whether the therapeutic intervention scoring system (TISS) reliably reflects the cost of the overall intensive care unit (ICU) population, subgroups of that population and individual ICU patients. Design: Prospective analysis of individual patient costs and comparison with TISS. Setting: Adult, 12 bedded general medical and surgical ICU in a university teaching hospital. Subjects: Two hundred fifty-seven consecutive patients including 52 coronary care (CCU), 99 cardiac surgery (CS) and 106 general ICU (GIC) cases admitted to the ICU during a 12-week period in 1994. A total of 916 TISS-scored patient days were analysed Main outcome measures: A variable cost (VC) that included consumables and service usage (nursing, physiotherapy, radiology and pathology staff costs) for individual patients was measured daily. Nursing costs were calculated in proportion to a daily nursing dependency score. A fixed cost (FC) was calculated for each patient to include medical, technical and clerical salary costs, capital equipment depreciation, equipment and central hospital costs. The correlation between cost and TISS was analysed using regression analysis. Results: For the whole group (n = 257) the average daily FC was £ 255 and daily VC was £ 541 (SEM 10); range £ 23–£ 2,806. In the patient subgroups average daily cost (FC + VC) for CCU was £ 476 (SEM 17.5), for CS £ 766 (SEM 13.8) and for GIC £ 873 (SEM 13.6). In the group as a whole, a strong correlation was demonstrated between VC and the TISS for each patient day (r = 0.87, p < 0.001) and this improved further when the total TISS score was compared with the total VC of the entire patient episode (r = 0.93, p < 0.001). This correlation was maintained in CCU, CS and GIC patient cohorts with only a small median difference between actual and predicted cost (2.2 % for GIC patients). However, in the individual patient, the range of error was up to ± 65 % of the true variable cost. For the whole group the variable cost per TISS point was £ 25. Conclusion: These results demonstrate that TISS reliably measures overall ICU population costs as well as those of the subgroups CCU, CS and GIC. However, the relationship between TISS and cost is less reliable for the individual patient. Received: 4 August 1997 Accepted: 22 March 1998  相似文献   
7.
8.
9.
报道了氯仿重结晶的棉酚的化学性质,样品在不同温度下干燥恒重后,经熔点、薄层层析、紫外光谱、红外光谱、X-射线衍射、热重量分析、元素(C,H,Cl)分析及棉酚合量测定等一系列的分析,确证了在60℃以下棉酚与氯仿成溶剂化物(solvate)。随着干燥温度的升高或在室温长时间的贮存,此现象逐渐消失,100℃真空干燥恒重后成为纯棉酚。  相似文献   
10.
Perforated duodenal ulcer and cigarette smoking.   总被引:1,自引:0,他引:1       下载免费PDF全文
Whilst the association between smoking and peptic ulceration has been reported previously, the relationship between smoking and the complications of ulcers, such as perforation, bleeding or acute painful exacerbation, has not been examined. In a retrospective study comparing 275 emergency admissions for peptic ulcer with 275 controls, cigarette smoking was significantly more common only in those with a perforated duodenal ulcer. Of 128 patients with perforated duodenal ulcers, 110 (86%) were cigarette smokers compared with 65 (51%) of the 128 matched controls (X2, P less than 0.01). Cigarette smoking in patients with bleeding or acutely exacerbated ulcers was not significantly more common than in controls. These findings strongly suggest a particular association between smoking and perforated duodenal ulcer.  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