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   7951篇
  免费   587篇
  国内免费   31篇
耳鼻咽喉   136篇
儿科学   302篇
妇产科学   187篇
基础医学   1102篇
口腔科学   124篇
临床医学   711篇
内科学   1446篇
皮肤病学   97篇
神经病学   895篇
特种医学   222篇
外科学   1140篇
综合类   105篇
一般理论   15篇
预防医学   563篇
眼科学   208篇
药学   568篇
中国医学   10篇
肿瘤学   738篇
  2023年   79篇
  2022年   148篇
  2021年   266篇
  2020年   188篇
  2019年   212篇
  2018年   263篇
  2017年   221篇
  2016年   241篇
  2015年   254篇
  2014年   327篇
  2013年   421篇
  2012年   625篇
  2011年   536篇
  2010年   350篇
  2009年   262篇
  2008年   399篇
  2007年   440篇
  2006年   380篇
  2005年   351篇
  2004年   341篇
  2003年   323篇
  2002年   324篇
  2001年   134篇
  2000年   110篇
  1999年   136篇
  1998年   63篇
  1997年   58篇
  1996年   44篇
  1995年   38篇
  1994年   30篇
  1993年   29篇
  1992年   71篇
  1991年   64篇
  1990年   55篇
  1989年   68篇
  1988年   51篇
  1987年   53篇
  1986年   50篇
  1985年   58篇
  1984年   42篇
  1983年   35篇
  1982年   34篇
  1981年   28篇
  1979年   48篇
  1978年   26篇
  1977年   25篇
  1976年   25篇
  1975年   22篇
  1973年   26篇
  1972年   26篇
排序方式: 共有8569条查询结果,搜索用时 62 毫秒
191.
192.
193.
The aim of the study was to develop simple algorithm for non-invasive estimating probability of the presence of CAD to optimize indications for cardiac catheterization. A prospective collection of clinical, electrocardiography (ECG), exercise electrocardiography (EE), dobutamine stress echocardiography (SE) and catheterization data was performed. All patients (n = 551, 65% male) complaining of chest pain, without prior history of myocardial infarction undergone EE (regarded as positive on the basis of > or = 1 mm ST-depression) SE (ischemia was defined as new or worsening wall motion abnormalities using a 16-segment model) and coronary angiography (CA): CAD was defined as > or = 50% narrowing of at least one major vessel. Two algorithms were developed with the use of probability analysis by computer program which employs Bayes' theory. They incorporated pretest variables: (age, gender, chest pain classification according to Diamond), ECG and results of one or two non-invasive test: EE and (or) SE. The studied population was divided into 3 groups on the basis of pretest likelihood of CAD: 1. low (< 10%), 2. intermediate (10-70%, in man divided into intermediate--low.: 10-29% and intermediate--high: 30-70%) and 3. high (> 70%). RESULTS: The prevalence of CAD in studied population was 61%. The sensitivity of the algorithm is 96% and specificity was 44%. Sensitivity and specificity of EE and SE was respectively: 93%, 21% and 85%, 69%). CONCLUSIONS: 1. An algorithm derived in our study is simple and may be useful in decision making that relates to CA. 2. We showed that when the likelihood of CAD is high on the basis of initial evaluation, diagnostic non-invasive testing is not indicated before CA, when the probability is intermediate or low, implementation of first choice test should be different in women (SE) and men (EE).  相似文献   
194.
Adrenal-dependent hypertension syndromes are uncommon forms of hypertension. They include primary aldosteronism, pheochromocytoma, Cushing"s syndrome, and congenital adrenal hyperplasia. Pheochromocytomas are the cause of hypertension in 0.1% to 0.2% of hypertensive patients. Excess catecholamine release and other neural and humoral mechanisms contribute to the pathophysiology of hypertension. Patients with pheochromocytomas have a potentially curable cause of endocrine hypertension and, if undetected, pheochromocytomas confer a high risk for morbidity and mortality, especially during surgical procedures and pregnancy. All patients with incidental adrenal tumors, regardless of tumor size, should be biochemically screened for pheochromocytoma (especially before resection or needle biopsy) to avoid precipitation of a lethal hypertensive crisis.  相似文献   
195.
196.
197.
198.

Introduction

In normal conditions follicle-stimulating hormone receptors (FSHR) are expressed in the ovary and the testis. They can also be expressed in gonadal tumors. However, recently we have found FSHR immunostaining in pituitary adenomas, adrenal tumors and neuroendocrine tumors (carcinoids). The aim of this study was to determine whether the same occurs in thyroid tumors.

Material and methods

Thirty-six samples of surgically excised thyroids were examined. Follicle-stimulating hormone receptors immunostaining was performed on paraffin sections using the rabbit anti-human FSHR polyclonal antibody raised against a 1-190 amino acid sequence from the human FSHR (sc-13935, Santa Cruz).

Results

Normal thyroid follicles do not show immunopositivity for FSHR. The same concerns the majority of benign lesions, diagnosed as hyperplasia nodularis or thyroid adenomas. However, positive FSHR immunostaining in some follicles was observed. In all but one thyroid cancer (15 papillary, 10 follicular cancers and one case of anaplastic thyroid cancer) 10–100% of tumor cells exhibit positive FSHR immunostaining. In about 40% of samples FSHR immunoreactivity can be observed also in the endothelia of intrathyroidal blood vessels. This immunopositivity was more frequent in the samples of thyroid cancers (13/27) than in benign lesions (2/9).

Conclusions

Ectopic positive FSHR immunostaining is also present in thyroid cancers, and, to a lesser degree, in benign lesions but not in the normal thyroid epithelium.  相似文献   
199.
200.
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