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   708篇
  免费   49篇
  国内免费   3篇
耳鼻咽喉   3篇
儿科学   5篇
妇产科学   7篇
基础医学   33篇
口腔科学   52篇
临床医学   99篇
内科学   244篇
皮肤病学   1篇
神经病学   21篇
特种医学   11篇
外科学   85篇
综合类   44篇
一般理论   1篇
预防医学   82篇
眼科学   1篇
药学   42篇
肿瘤学   29篇
  2022年   4篇
  2021年   12篇
  2020年   6篇
  2019年   19篇
  2018年   28篇
  2017年   13篇
  2016年   8篇
  2015年   15篇
  2014年   23篇
  2013年   20篇
  2012年   38篇
  2011年   39篇
  2010年   10篇
  2009年   9篇
  2008年   45篇
  2007年   33篇
  2006年   36篇
  2005年   39篇
  2004年   44篇
  2003年   30篇
  2002年   31篇
  2001年   16篇
  2000年   22篇
  1999年   16篇
  1998年   8篇
  1997年   6篇
  1996年   6篇
  1995年   7篇
  1994年   9篇
  1993年   4篇
  1992年   18篇
  1991年   8篇
  1990年   20篇
  1989年   9篇
  1988年   9篇
  1987年   10篇
  1986年   6篇
  1985年   8篇
  1984年   6篇
  1983年   6篇
  1979年   8篇
  1978年   4篇
  1977年   4篇
  1976年   6篇
  1974年   5篇
  1973年   6篇
  1971年   5篇
  1969年   3篇
  1968年   6篇
  1966年   2篇
排序方式: 共有760条查询结果,搜索用时 15 毫秒
1.
The visit of Dr. Trendley Dean to Dublin in the mid-1950s helped accelerate the decision to introduce water fluoridation as a public health measure in the prevention of caries in the Republic of Ireland. A challenge to the constitutional validity of the Health (Fluoridation of Water Supplies) Act 1960 failed and in 1964 the water supplies of Dublin city were fluoridated. Over the next seven to eight years all the major urban communities in the Republic of Ireland were fluoridated. Currently, 67 percent of the 3.5 million people in the country reside in fluoridated communities. Studies conducted over the last 20 years show that residents of fluoridated communities have better dental health than those in nonfluoridated communities—the mean dmft is lower in children and the number of natural teeth present in adults is higher.  相似文献   
2.
3.
4.
Long-term treatment with oral torsemide was studied to determine its effectiveness in maintaining steady-state fluid balance in patients with chronic renal insufficiency by using a placebo-controlled, double-blind, random-off design. Patients with stable chronic renal insufficiency were initially titrated and then stabilized on torsemide. Once stabilized on torsemide, patients were randomly assigned in a double-blind fashion to continue on their titrated dose of torsemide or to receive a placebo. Of the 82 patients enrolled in the study, 68 were randomized to torsemide (n = 34) or placebo (n = 34). Patients who received the placebo showed a significantly greater (p < 0.001) mean increase in body weight (3.55 lb) than did patients who remained on torsemide (0.46 lb). Approximately two-thirds of the weight gain observed in the placebo group occurred during the first 3 days after randomization. Patients continued to receive treatment unless they developed fluid accumulation that was considered deleterious to their clinical state as determined by the investigator. In the placebo group a greater number of patients discontinued treatment because of weight gain or fluid accumulation. The mean number of days on treatment after randomization was significantly higher (p < 0.001) for patients who received torsemide (26 days) than for patients who received the placebo (16 days). The lack of weight gain in the torsemide group was associated with a higher percentage of patients who showed no change or an improvement in peripheral edema status (79%) than in placebo patients (35%). No patient was withdrawn from the study because of hyperkalemia or hypokalemia. The adverse effects reported during the study were as anticipated for patients with chronic renal insufficiency that is often complicated by other underlying illnesses.  相似文献   
5.
6.
7.
Chronic lead exposure has been associated with elevated blood pressure in epidemiological studies. It is not known whether the previously observed relation between blood lead and hypertension persists after significant reductions have been made in environmental lead contamination. We examined the relation between blood lead levels and blood pressure in a representative sample of 14 952 whites and blacks aged 18 years or older who participated in the Third National Health and Nutrition Examination Survey. Blood lead was measured by atomic absorption spectrophotometry and blood pressure by standard sphygmomanometry. Mean blood lead levels were significantly higher for black men and women (5.4 and 3.4 microg/dL, respectively) compared with white men and women (4.4 and 3.0 microg/dL, respectively). After multivariate adjustment for important covariables, each standard deviation higher blood lead (3.3 microg/dL) was associated with a 0.82 (95% confidence interval [CI], 0.19 to 1.44) mm Hg and a 1.55 (95% CI, 0.47 to 2.64) mm Hg higher systolic blood pressure among black men and women, respectively. In contrast, blood lead level was not associated with blood pressure among white men or women. The multivariate-adjusted odds ratio (95% CI) of hypertension associated with a 1-SD higher level of blood lead was 1.08 (95% CI, 0.99 to 1.19) for black men and 1.39 (95% CI, 1.21 to 1.61) for black women. These findings suggest that increased levels of blood lead remain an important environmental risk factor for elevated blood pressure in blacks.  相似文献   
8.
OBJECTIVES: The aim of this study was to assess the utility of tissue Doppler echocardiography in the setting of repaired transposition of the great arteries when the right ventricle (RV) functions as the systemic ventricle. BACKGROUND: Myocardial acceleration during isovolumic contraction, "isovolumic myocardial acceleration" (IVA), has been validated as a sensitive non-invasive method of assessing RV contractility. Although traditional indexes may be less valid for the abnormal RV, the relative insensitivity of IVA to an abnormal load makes it a potentially powerful clinical tool for the assessment of RV disease. METHODS: We examined 55 controls and 80 patients (mean age 22 years) with transposition, who had undergone atrial repair at age 8 (0.3 to 72) months. A subgroup of 12 underwent cardiac catheterization. The RV systolic function was derived by analysis of pressure-volume relationships and IVA both at rest and during dobutamine stress. In all 80, myocardial velocities were sampled in the RV free wall. RESULTS: During dobutamine (10 microg/kg/min for 10 min), the increase of IVA mirrored the increase in end-systolic elastance (r = 0.69, p < 0.02). In the group as a whole, IVA was reduced compared with the subpulmonary RV and the systemic left ventricle of controls. There was abnormal wall motion in 44 patients, which was associated with reduced IVA. Diastolic myocardial velocities were also abnormal but unrelated to the presence of wall motion abnormalities. CONCLUSIONS: The IVA can accurately assess changes in RV contractile function in patients with an RV as the systemic ventricle. Global long-axis RV function is reduced in patients with transposition, and this is associated with abnormal regional function.  相似文献   
9.
10.
High blood pressure (BP) is a major risk factor for coronary heart disease, heart failure, stroke, chronic kidney disease, end stage renal disease, and a variety of other clinically important outcomes. Results from the surveys described in this issue and elsewhere underscore a common finding that hypertension is both highly prevalent and insufficiently treated and controlled. Recognizing the differences in sampling and survey measurement techniques, the reported prevalence of hypertension (SBP/DBP >/=140/90 mmHg or treatment with antihypertensive medication) in adults exceeded 25% in all of the surveys reported in this issue. In Latvia, the prevalence of hypertension for 25-64-year-old adults in the general population was 46.1%. Control of hypertension with medication to an SBP/DBP <140/90 mmHg in the general population ranged from as low as 12% to a high of only 29%. Data from other parts of the world provide an equally distressing picture of what is (not) being accomplished in treatment and control of hypertension at the level of the general population. These data provide testimony to an urgent need for greater attention to the treatment and control of hypertension in populations around the world. This was the basis for a panel discussion at the International Society of Hypertension satellite conference The Epidemiology of Hypertension-Regional Differences in Treatment and Control. Panel participants included Drs P Whelton, S Sonkodi, DG Beevers, JG Fodor, H Elliot, R Cifkova, A Nissinen, A Javor, and there was active participation of other symposium attendees. The following summarizes key elements of the discussion and recommendations of the panel.  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