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   1113篇
  免费   70篇
  国内免费   9篇
耳鼻咽喉   13篇
儿科学   26篇
妇产科学   24篇
基础医学   118篇
口腔科学   13篇
临床医学   150篇
内科学   279篇
皮肤病学   43篇
神经病学   32篇
特种医学   200篇
外科学   90篇
综合类   18篇
预防医学   54篇
眼科学   9篇
药学   63篇
中国医学   2篇
肿瘤学   58篇
  2023年   7篇
  2022年   15篇
  2021年   19篇
  2020年   13篇
  2019年   18篇
  2018年   19篇
  2017年   25篇
  2016年   16篇
  2015年   18篇
  2014年   20篇
  2013年   48篇
  2012年   35篇
  2011年   51篇
  2010年   27篇
  2009年   33篇
  2008年   36篇
  2007年   32篇
  2006年   52篇
  2005年   35篇
  2004年   42篇
  2003年   32篇
  2002年   39篇
  2001年   35篇
  2000年   27篇
  1999年   30篇
  1998年   20篇
  1997年   34篇
  1996年   30篇
  1995年   19篇
  1994年   27篇
  1993年   14篇
  1992年   18篇
  1991年   26篇
  1990年   22篇
  1989年   28篇
  1988年   23篇
  1987年   20篇
  1986年   26篇
  1985年   20篇
  1984年   17篇
  1983年   7篇
  1982年   14篇
  1980年   8篇
  1979年   7篇
  1978年   8篇
  1977年   9篇
  1975年   8篇
  1971年   12篇
  1970年   6篇
  1966年   6篇
排序方式: 共有1192条查询结果,搜索用时 15 毫秒
101.
102.
Macroamylasaemia was produced in vitro by incubation of hydroxyethylstarch with serum, and in vivo by intravenous infusion of hydroxyethylstarch. Gel filtration on Sephadex G-100 revealed distinct differences in molecular size distribution between such hydroxyethylstarch-induced macroamylase and the usual form of naturally occurring macroamylase which was observed in a few patients from our hospital. Further studies demonstrated that the gel filtration elution pattern of amylase activity in serum containing hydroxyethylstarch-induced macroamylase is significantly altered with time in vitro and in vivo, probably because of an enzymatic degradation of the hydroxyethylstarch components of the macromolecular complexes. In a healthy volunteer the serum amylase activity was elevated to a maximum of 797 u/l and the renal clearance rate of amylase was diminished to a minimum of 0.3 ml/min after infusion of 500 ml of a 6% solution of hydroxyethylstarch, as compared to 300 u/l, and 0.95 ml/min, respectively, during the pre-infusion period.  相似文献   
103.
We compared the clinical characteristics of 50 patients from three unrelated families with familial hemiplegic migraine (FHM) linked to chromosome 19, with those of 20 patients from two families with FHM not linked to chromosome 19. We found no significant differences for age at onset, frequency and duration of attacks, duration of the paresis, and occurrence of basilar migraine symptoms. In the linked families, significantly more patients reported unconsciousness during attacks (39%, vs 15%; p<0.05) and provocation of attacks by mild head trauma (70% vs 40%; p< 0.05). In one linked family patients also displayed chronic progressive cerebellar ataxia, whereas in one unlinked family benign infantile convulsions occurred in addition to FHM. Interestingly, so far an association with cerebellar ataxia was only described in chromosome 19-linked families. FHM linked to chromosome 19 and FHM unlinked to chromosome 19 do not differ with respect to clinical features.  相似文献   
104.
We conducted an open observational study with blinded endpoint evaluation to validate the use of the Duke treadmill score in identifying patients likely to require coronary intervention. We studied 101 consecutive patients referred for coronary angiography from a cardiology clinic. All patients had a Bruce protocol exercise test. A 70% stenosis was regarded as significant. Patients were referred for percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) surgery, if indicated. The Duke score was calculated as follows: exercise time (min) - (5 x ST segment deviation [mm]) - (4 x angina index [text]). Patients were classified into low, medium and high risk. The patients at high risk are more likely to have a significant stenosis (53/58 vs 30/43: p = 0.01 [OR 4.59 95% CI 1.34-16.6]) and require CABG or PTCA (47/58 vs 16/43: p < 0.001 [OR 7.21 95% CI 2.69-19.8]) than those at medium/low risk. Multiple logistic regression analysis, including ST segment depression, exercise time and symptoms shows that the score independently predicts a significant stenosis (p = 0.002) and the need for coronary intervention (p = 0.001). Introducing the score can help to identify those patients who need priority investigation.  相似文献   
105.
106.
BACKGROUND: Expensive devices have been developed for the collection and transfusion of blood salvaged after hip or knee arthroplasty. STUDY DESIGN AND METHODS: The volume of salvaged red cells was measured for the first 6 hours after operation. This volume was compared to total red cell loss during hospitalization and to the volume of allogeneic red cells transfused. RESULTS: Mean postoperative red cell loss in 31 patients following hip replacement was 55 +/− 29 mL and that in 20 patients following knee replacement was 121 +/− 50 mL. The 6-hour wound drainage represented 8.7 and 16.8 percent of overall red cell loss during hospitalization for hip and knee replacement, respectively. The transfusion of postoperatively salvaged red cells would have supplanted transfusion of less than one-third of a unit of allogenic blood after hip replacement and two-thirds of a unit after knee replacement. Only three patients (5.9%) lost red cell volume in the drainage equivalent to or in excess of 1 unit of red cells (180 mL). The volume of red cells salvaged postoperatively bore no relationship to perioperative red cell losses as a whole. CONCLUSION: The relatively small red cell loss in the postoperative period in most arthroplasty patients does not appear to justify the routine use of this technique for the recovery of autologous blood.  相似文献   
107.
BACKGROUND: The primary aim of the study was to estimate the incidence of Crohn's disease (CD) and ulcerative colitis (UC), collectively known as inflammatory bowel disease (IBD), in Malta in a well-defined population during a 13-year study period. METHODS: Diagnostic criteria for CD and UC were defined. A diagnosis of IBD was obtained from the histopathology reports at St. Luke's Hospital, Malta, between January 1993 and December 2005. The date of diagnosis was defined as the date of the first histopathology report revealing signs of IBD. RESULTS: Incidence rates were standardized using the direct method on the European Standard Population. The mean incidence of UC in males was 8.16 per 100,000 per year and for females was 7.59 per 100,000 per year, while that for CD in males was 0.96 per 100,000 per year and for females 1.622 per 100,000 per year. Using linear regression, in UC there is an almost significant (P = 0.069) increasing trend with time but no difference by gender (P = 0.591). On the other hand, in CD there is no significant trend with time (P = 0.555) but almost a significant difference by gender (P = 0.078). CONCLUSIONS: This is the first Maltese study in which the incidence of IBD has been recorded. In Malta the incidence of UC is similar to the overall incidence of other European countries while the incidence of CD is lower. In fact, the incidence rates of CD are among the lowest in Europe, similar to other southern European countries.  相似文献   
108.
109.
A cDNA for endothelial leukocyte adhesion molecule 1 (ELAM-1) was isolated by transient expression in COS-7 cells of a subtracted cDNA library from cytokine-treated human umbilical vein endothelial cells (HUVECs), with selection of ELAM-1-expressing clones by adhesion of transfected cells to the human promyelocytic cell line HL-60. This cloning method requires neither antibody nor purified ligand. ELAM-1-expressing COS cells bind the promyelocytic cell line HL-60 by a Ca2(+)-dependent but temperature-independent mechanism. Although ELAM-1 is homologous to mammalian lectins, its interaction with HL-60 cells is not inhibited by simple carbohydrate structures. ELAM-1-expressing COS cells also bind human neutrophils and the human colon carcinoma cell line HT-29, but not the B-cell line Ramos. However, Ramos cells adhere to cytokine-treated HUVECs but not control HUVECs, confirming the existence of other inducible adhesion molecules. In addition, the binding of HL-60 cells or neutrophils to ELAM-1-expressing COS cells is not inhibited by a monoclonal antibody (60.3) directed to an inhibitory epitope on CD18, indicating that the ELAM-1 ligand, although uncharacterized, is not a member of the CD11/CD18 family.  相似文献   
110.

Background

Little information is available on the effect of a follow-up strategy in celiac disease patients during gluten-free diet.

Aims

To assess 5 year time course of t-transglutaminase antibodies (t-TG) in celiac disease patients enrolled in a community based follow-up program.

Methods

Annual t-TG testing and periodical clinic visit in 2245 patients.

Results

Proportion of patients with negative t-TG progressively increased from 83% to 93% during the 5-year follow-up: poor adherence to gluten-free diet (HR 4.764), long duration of gluten-free diet (HR 0.929) and female gender (HR 1.472) were independently associated with serological outcome. In individual patients, 69% tested t-TG “persistently negative”, 1% “persistently positive” and 30% “intermittently negative or positive”. By applying mathematical modelling to t-TG conversion rates observed in this latter group at beginning and end of the follow-up program, the predicted proportion of t-TG negative population increased from 90% to 95% over 5 years.

Conclusions

Time-course of t-TG serology in the community fluctuates in 1/3 of celiac disease patients suggesting inconstant adherence to gluten-free diet and need of follow-up strategy. Periodical serological and clinical follow-up is a viable and efficacious strategy to promote adherence to gluten-free diet as inferred from time-course of t-TG serology.  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