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   852篇
  免费   112篇
  国内免费   16篇
耳鼻咽喉   3篇
儿科学   40篇
妇产科学   8篇
基础医学   163篇
口腔科学   16篇
临床医学   82篇
内科学   170篇
皮肤病学   8篇
神经病学   58篇
特种医学   148篇
外科学   54篇
综合类   62篇
预防医学   52篇
眼科学   16篇
药学   55篇
中国医学   1篇
肿瘤学   44篇
  2021年   13篇
  2019年   11篇
  2018年   11篇
  2017年   9篇
  2016年   10篇
  2015年   16篇
  2014年   13篇
  2013年   30篇
  2012年   30篇
  2011年   40篇
  2010年   21篇
  2009年   25篇
  2008年   17篇
  2007年   31篇
  2006年   23篇
  2005年   19篇
  2004年   11篇
  2003年   12篇
  2002年   21篇
  2001年   13篇
  2000年   16篇
  1999年   28篇
  1998年   35篇
  1997年   47篇
  1996年   55篇
  1995年   23篇
  1994年   27篇
  1993年   29篇
  1992年   9篇
  1991年   10篇
  1990年   13篇
  1989年   26篇
  1988年   30篇
  1987年   18篇
  1986年   27篇
  1985年   17篇
  1984年   12篇
  1983年   12篇
  1982年   17篇
  1981年   12篇
  1980年   11篇
  1979年   11篇
  1978年   14篇
  1977年   11篇
  1976年   16篇
  1975年   13篇
  1971年   7篇
  1970年   8篇
  1969年   6篇
  1968年   6篇
排序方式: 共有980条查询结果,搜索用时 15 毫秒
11.
Summary The effects of 9 weeks of training on responses of plasma hormones to swimming were studied in eight competitive swimmers who had not trained for several months. Two types of swimming tests were used: (1) 200 yd, a high intensity, exhausting type of exercise in which maximal effort was required both before and after training, and (2) 1000 yd, a pace type of exercise in which subjects swam as fast as possible prior to training and at the same rate after training. Plasma levels of glucagon increased and of insulin decreased during 1000 yd of swimming, but were not altered by 200 yd of swimming. No training effects were apparent in responses of plasma insulin and glucagon to these short-term, high intensity exercise tests. During the 1000 yd swim, plasma adrenaline was 0.8 ng/ml before vs. 0.1 ng/ml after training. Plasma noradrenaline response decreased from 3.4 to 1.2 ng/ml as a result of training. In the 200 yd swim, adrenaline, but not noradrenaline, was lower after training.R. C. Hickson and R. K. Conlee were postdoctoral research trainees supported by NIH Training Grant AM-05341.J. M. Hagberg was a postdoctoral research trainee supported by NIH Training Grant HL-07081.  相似文献   
12.
The "Asthma Self-Efficacy Scale"   总被引:4,自引:0,他引:4  
According to Bandura, a person's expectations that a favorable outcome will follow a particular behavior are not sufficient to promote the occurrence of the behavior; the person must also believe that he or she will be effective at performing the behavior. The latter is referred to as self-efficacy. It has become a major focus in assessing patient performance of skills required to manage their illness. The present paper describes the development, testing, and applicability of an instrument for assessing self-efficacy in asthmatic patients. It notes that the Asthma Self-Efficacy Scale is not only a reliable paper-and-pencil instrument, but that it has a wide potential applicability throughout health care settings in measuring self-efficacy in asthmatic patients. The Asthma Self-Efficacy Scale is included.  相似文献   
13.
Four patients with proved osteopetrosis (three with the infantile malignant form and one with the benign form) were examined with magnetic resonance imaging at 1.5 T. All patients were studied in the coronal and sagittal planes using both short and long repetition time/echo time sequences. The infantile malignant form was characterized by a complete lack of signal from the marrow alternating with a signal intensity equivalent to that of the intervertebral disks, resulting in a "stepladder" appearance. In the benign form or after successful marrow transplantation in the infantile malignant form, intermediate or high signal intensity in the vertebrae was noted, suggesting the presence of some marrow elements.  相似文献   
14.
15.
急性有机磷农药中毒120例的救治   总被引:1,自引:0,他引:1  
0 引言 近年来 ,我科在救治急性有机磷农药 (organophos-phorus,OP)中毒方面 ,积累了一些经验 ,现报告如下 .1 对象和方法1 .1 对象 本组 1 2 0例符合《急诊急救学》中的诊断标准 [1 ](男 2 9例 ,女 91例 ) ,年龄 1 .5~ 70岁 ,平均 2 8.6岁 .经口中毒 99例 ,经皮肤中毒 2 1例 .轻度中毒 1 5例 ,中度中毒 42例 ,重度 (含极重度 )中毒 6 3例 . 1 996年 39例 ,1 997年 43例 ,1 998年 38例 . DDV 79例 ,乐果 2 0例 ,混合性中毒 1 0例 ,水胺磷 3例 ,氧化乐果、 391 1、 1 0 5 9、对硫磷各 2例 ,敌百虫 1例 ,药名不详 1 0例 .服毒量 >2 5 …  相似文献   
16.
This report describes a new method of custom making cranial titanium plates for the repair of skull defects. We have combined 3D CT imaging and surface modelling with rapid prototyping (RP) technology to produce physical models of our patients' skulls from which custom titanium plates were made. We have expanded the use of image processing tools applied to the CT image data to fabricate a representation of the skull defect. Medical RP models are relatively expensive and particular attention has been paid to developing image processing methods to reduce costs. Our technique used the patient as their own model and generated data from the contralateral side of the head where appropriate. We present the results of 10 patients who have had a custom made cranial titanium plate fitted and discuss the models for these cases. The benefits of our custom made titanium plates are reduced patient attendances to hospital and a more accurate titanium plate which has improved fitting and cosmesis.  相似文献   
17.
It really is a great pleasure for me to write this paper. Before EDTNA was born, when it was a only a glimmer in its Mother's eye, I fell in love with renal nursing. And it was through renal nursing that I became involved with the Royal College of Nursing of the United Kingdom, which has played such an important role in advancing the art and science of nursing, and in encouraging the development of clinical nursing expertise, and the role of specialist practice.  相似文献   
18.

Objective

To investigate age and sex differences in the utilisation of hospital services for ischaemic heart disease.

Design

Analysis of routine mortality data and hospital activity data.

Setting

South West Thames Regional Health Authority.

Subjects

Residents of the South West Thames Regional Health Authority who in 1991 either died from ischaemic heart disease or were admitted to an NHS hospital in England and Wales with a main diagnosis of ischaemic heart disease.

Main outcome measures

Ratio of consultant episodes to deaths from ischaemic heart disease (as a proxymeasure of the utilisation of hospital care), and the percentages of consultant episodes in which further investigation (angiography or catheterisation) or revascularisation treatment (coronary artery bypass grafting or angioplasty) were carried out.

Results

The ratio of episodes to deaths was similar in men and women (odds ratio for men vs. women 0.96, 95% confidence intervals 0.90 to 1.03). The percentage of episodes in which further investigation was carried out was higher in men than women (odds ratio for men vs. women 1.46, 95% confidence intervals 1.25 to 1.70) as was the percentage of episodes in which revascularisation treatment was carried out (odds ratio for men vs. women 1.46, 95% confidence intervals 1.20 to 1.77). The ratio of episodes to deaths, the percentage of episodes in which further investigation was carried out, and the percentage of episodes in which revascularisation treatment was carried out all declined with age (all p values <0.001).

Conclusions

Women with ischaemic heart disease are as likely as men to be admitted to hospital, but afteradmission are less likely to undergo further investigation and revascularisation treatment. Elderly patients with ischaemic heart disease are less likely than younger patients to be admitted to hospital; after admission, they are also less likely to undergo further investigation and revascularisation treatment. Further research is needed to determine whether these age and sex differences in the use of hospital services are clinically justified.  相似文献   
19.
Davis  GD; Fulton  RE; Ritter  DG; Mair  DD; McGoon  DC 《Radiology》1978,128(1):133-144
Of 181 patients with severe congenital pulmonary atresia and ventricular septal defect or "type IV truncus" (an obsolete term), all but 11% had true central pulmonary arteries. These arteries were demonstrable by large serial biplane angiograms using multiple selective injections into collateral vessels, frequent photographic subtraction, and occasional pulmonary vein-wedge angiograms. These techniques are extremely important for accurate diagnosis and in planning corrective or palliative surgery, which was done in 77% of patients with pulmonary arteries.  相似文献   
20.
Summary Chromatographic analysis of 3,5-cyclic nucleotide phosphodiesterase (PDE) isoenzymes in the cytosol of human neutrophils shows the predominant presence of PDE IV (cAMP specific) and PDE V (cGMP specific). PDE IV is characterized by (1) cAMP selectivity, (2) a KM for cAMP of 1.2 M and (3) a typical rank order of IC 50-values for PDE inhibitors: 0.13, 0.17, 47 and 9.5 M for PDE IV selective rolipram, PDE III/IV selective zardaverine, PDE III selective motapizone and unselective 3-isobutyl-l-methylxanthine (IBMX), respectively. Functions of polymorphonuclear leukocytes (PMN) such as N-formylmethionyl-leucyl-phenylalanine (fMLP)-stimulated superoxide release and fMLP/thimerosal elicited leukotriene (LT) biosynthesis are inhibited by these PDE inhibitors with the same rank order and even lower IC50-values. Measurements of changes in cytosolic Cai in Fura-2 loaded PMN demonstrate a transient Cai increase after stimulation with 0.1 M fMLP and an additional sustained elevation of Cai levels in the presence of thimerosal. PDE inhibitors suppress this sustained phase of Cai release with the same rank order of IC50-values as LT biosynthesis. The correlation between fMLP/thimerosal-induced LT biosynthesis and Cai levels reveal a Cai threshold of 150 nM for arachidonic acid metabolism. cAMP levels in PMN were elevated by PDE inhibitors alone by less than 2-fold. In the presence of fMLP however, cAMP was increased up to 10-fold and the efficacy of PDE inhibitors to increase cAMP paralleled their potency to inhibit PDE IV. It is concluded that (1) suppression of PMN functions is achieved by PDE IV inhibition, (2) necessary cAMP elevations are within 50% increase, (3) superoxide release was affected by cAMP/protein kinase A (PKA) directly whereas (4) for inhibition of LT biosynthesis a cAMP related reduction of Ca-influx is involved. Send offprint requests to Ch. Schudt at the above address  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