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   890篇
  免费   50篇
  国内免费   39篇
耳鼻咽喉   2篇
儿科学   35篇
妇产科学   17篇
基础医学   94篇
口腔科学   18篇
临床医学   118篇
内科学   200篇
皮肤病学   9篇
神经病学   51篇
特种医学   170篇
外科学   64篇
综合类   25篇
预防医学   51篇
眼科学   8篇
药学   73篇
肿瘤学   44篇
  2021年   11篇
  2020年   8篇
  2019年   10篇
  2018年   17篇
  2017年   11篇
  2016年   11篇
  2015年   16篇
  2014年   23篇
  2013年   26篇
  2012年   28篇
  2011年   27篇
  2010年   27篇
  2009年   35篇
  2008年   20篇
  2007年   42篇
  2006年   19篇
  2005年   14篇
  2004年   16篇
  2003年   13篇
  2002年   18篇
  2001年   16篇
  2000年   14篇
  1999年   17篇
  1998年   54篇
  1997年   44篇
  1996年   38篇
  1995年   32篇
  1994年   25篇
  1993年   35篇
  1992年   12篇
  1991年   21篇
  1990年   13篇
  1989年   30篇
  1988年   22篇
  1987年   25篇
  1986年   17篇
  1985年   28篇
  1984年   16篇
  1983年   16篇
  1982年   15篇
  1981年   19篇
  1980年   20篇
  1979年   5篇
  1978年   8篇
  1977年   8篇
  1976年   10篇
  1975年   5篇
  1973年   4篇
  1972年   5篇
  1967年   3篇
排序方式: 共有979条查询结果,搜索用时 15 毫秒
61.
Wooden foreign bodies in soft tissue: detection at US   总被引:4,自引:0,他引:4  
  相似文献   
62.
Emphysema in the renal allograft   总被引:1,自引:0,他引:1  
Two diabetic patients in whom emphysematous pyelonephritis developed after renal transplantation are described. Clinical recognition of this unusual and serious infection is masked by the effects of immunosuppression. Abdominal radiographic, ultrasound, and computed tomography findings are discussed. The clinical presentation includes urinary tract infection, sepsis, and acute tubular malfunction of the allograft in insulin-dependent diabetics.  相似文献   
63.
64.
OBJECTIVE: Circulating endothelin-1 (ET-1) levels have been reported to be associated with vascular complications and endothelial dysfunction in nontransplanted patients. The aim of this study was to investigate the relationship between ET-1 levels and major cardiovascular (CV) risk factors in renal transplant (RTX) patients with stable graft function. METHODS: ET-1 levels were determined in 156 RTX patients and the relationship between circulating ET-1 levels and CV risk factors including age, gender, kidney function, blood lipids, diabetes, and hypertension was studied. RESULTS: Circulating ET-1 levels were found to be positively correlated with creatinine (r = 0.25, p < 0.01) and systolic blood pressure (r = 0.20, p < 0.05) and inversely correlated with high-density lipoprotein cholesterol (HDL-C) levels (r = -0.27, p < 0.01). Patients with high and intermediate total cholesterol/HDL-C ratios (TC/HDL-C) had significantly higher ET-1 levels when compared to patients with low ratios (7.02 +/- 3.74, 6.79 +/- 2.67, and 5.37 +/- 3.04 pg/ml, respectively, p < 0.002). Only creatinine, HDL-C, and age >40 years were shown to be independent correlates for ET-1 levels according to multivariate analyses. Interestingly, ET-1 levels were significantly higher (+26%, p < 0.03) in RTX patients with documented CV disease, as compared to those without, when matched for age, gender, and presence of diabetes. CONCLUSIONS: Increased circulating ET-1 levels are associated with low HDL-C and documented CV disease in RTX. This is likely a reflection of vascular endothelial damage and dysfunction and therefore may represent an increased risk for atherosclerosis.  相似文献   
65.
The experience of pain and emergent osteoarthritis of the knee   总被引:3,自引:0,他引:3  
Discrepancies exist between radiographic osteoarthritis of the knee (OAK) and report of knee joint pain. Little is known about how these two definitions of osteoarthritis (OA) and their correlates differ between African American (AA) and Caucasian (CA) women. OBJECTIVE: We compared the prevalence of radiographic OAK and knee joint pain in AA and CA women, and the congruency of these outcomes according to age, body size, and knee injury. DESIGN: A cross-sectional study of African American and Caucasian women aged 40-53 years (N=829) in Southeast Michigan used the Kellgren and Lawrence Atlas of Standard Radiographs of Arthritis to characterize radiographs of both knee joints (weight bearing) and self-report of knee pain. RESULTS: Current pain was a significantly more sensitive predictor of radiographic OAK among AA women (Se=0.51) compared to CA women (Se=0.35). Specificity was similar between AA women (Sp=0.77) and CA women (Sp=0.82). Positive predictive value was significantly greater for AA compared with CA women (PV+=0.40 and PV+=0.15, respectively). The odds of having radiographic OAK increased with BMI >32 kg/m(2) in both groups. Knee pain was related to BMI in CA women, but not AA women. Previous knee injury was associated with knee pain in both AA and CA women (OR=3.0 and OR=2.4). CONCLUSIONS: Joint pain in AA women was more likely to be associated with radiographic OAK as compared with CA women. This suggests differences in these two groups in both how pain is experienced in the OAK process and in the prevalence of non-OAK related pain in knee joints.  相似文献   
66.
The goal of the study was to compare caregivers who used psychotropic drugs with caregivers who were non-users in order to pinpoint differences in coping styles between the two groups. We performed a secondary analysis of a study on the stress and psychological well-being of persons caring for relatives with dementia. We compared elderly caregivers, as either psychotropic drug users (n = 61) or non-users (n = 133), over various psychosocial characteristics relating to the care-giving context. Results reveal that users, as compared to non-users were: (a) more disturbed (appraised a greater stress) by the relative's dysfunctional behaviours, after controlling for the frequency of the behaviours; and (b) experienced more conflict during interpersonal interactions, although their appraisal of self-satisfaction with formal and informal support to their care-giving activities did not differ significantly. Strikingly, users combined and called on a greater number of problem-focused and emotion-reducing coping strategies than did non-users. They more frequently used affective regulation and information seeking coping styles. Stress-related measures (especially stress appraisal and conflict) contributed more to the variation in mental distress of users than of non-users. Results provide a theoretical and empirical rationale for therapeutic interventions such as the cognitive behavioural approach.  相似文献   
67.
Caloric restriction (CR) has been observed to retard aging processes and extend the maximum life span in rodents. In an effort to evaluate the effect of this nutritional intervention on physiologic variables in higher species, several nonhuman primate trials are ongoing. In particular, a study evaluating the independent effect of CR on the extent of atherosclerosis was initiated in 1993 in 32 adult cynomolgus monkeys. Therefore, the trial was designed to achieve identical cholesterol intake after animals were randomized to a control group or a calorie-restricted group (30% reduction from baseline caloric intake). The animals were routinely evaluated for glycated proteins, plasma insulin and glucose levels, insulin sensitivity, and specific measures for abdominal fat distribution by CT scans over a 4-year interval. The results from 4 years of intervention demonstrate that CR improves cardiovascular risk factors (such as visceral fat accumulation) and improves insulin sensitivity. In contrast to other primate studies with normolipidemic animals, CR had no independent effects on plasma lipid levels and composition in the presence of equivalent amounts of dietary cholesterol intake. Preliminary analysis of atherosclerotic lesion extent in the abdominal aorta has failed to demonstrate differences between control animals and CR animals. Follow- up studies are being conducted to determine the effect of CR on atherosclerosis extent in coronary and carotid arteries.   相似文献   
68.
69.
70.
K-Ⅱ系k阿片激动剂U-50488的同类物。通过部分离体和整体实验比较了K-Ⅱ与U-50488的药理作用。实验发现,K-Ⅱ抑制电刺激兔输精管收缩的IC50值为0.42 nmol/L,U-50488为26.5 nmol/L;K-Ⅱ抑制小鼠运动功能(横筛法)的ED50值为1.7 mg/g,U-50488为15.3 mg/kg;K-Ⅱ的小鼠LD50值为152.5 mg/kg,U-50488为118.4 mg/g;K-Ⅱ明显降低小鼠自发活动的作用比U-50488强5倍。结果表明,K-Ⅱ是一个药理作用较U-50488强的k受体激动剂。  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