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   14429篇
  免费   743篇
  国内免费   139篇
耳鼻咽喉   123篇
儿科学   262篇
妇产科学   147篇
基础医学   1598篇
口腔科学   273篇
临床医学   959篇
内科学   4101篇
皮肤病学   244篇
神经病学   893篇
特种医学   431篇
外科学   2843篇
综合类   68篇
预防医学   400篇
眼科学   179篇
药学   1021篇
中国医学   59篇
肿瘤学   1710篇
  2023年   106篇
  2022年   199篇
  2021年   446篇
  2020年   226篇
  2019年   310篇
  2018年   416篇
  2017年   254篇
  2016年   411篇
  2015年   426篇
  2014年   502篇
  2013年   578篇
  2012年   1002篇
  2011年   1055篇
  2010年   579篇
  2009年   433篇
  2008年   842篇
  2007年   916篇
  2006年   839篇
  2005年   862篇
  2004年   781篇
  2003年   640篇
  2002年   713篇
  2001年   231篇
  2000年   215篇
  1999年   211篇
  1998年   151篇
  1997年   133篇
  1996年   109篇
  1995年   103篇
  1994年   91篇
  1993年   79篇
  1992年   118篇
  1991年   135篇
  1990年   112篇
  1989年   113篇
  1988年   128篇
  1987年   103篇
  1986年   95篇
  1985年   104篇
  1984年   67篇
  1983年   70篇
  1982年   30篇
  1981年   43篇
  1980年   39篇
  1979年   44篇
  1978年   29篇
  1977年   26篇
  1973年   23篇
  1970年   18篇
  1969年   25篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Direct measurement of intra-arterial blood pressure (BP) for 24-h provides approximately 100,000 values that vary enormously, but each (BPi) can be expressed by the equation BPi = BP0 + DeltaBPi (BP0, base BP; DeltaBPi, BP increment, i=1, 2, ..., 100 x 10(3)). About 20% of outpatients with hypertension exhibit white-coat hypertension (WCH). In such patients, DeltaBPc (i = c; c, time at the clinic) is surmised to be large. A method for explaining the physiological factors in DeltaBPc and the estimation of base BP in the outpatient clinic is important. This study addresses this issue. A total of 293 subjects were divided into four groups: 1) WCH group, 45 individuals (office BP > or = 140/90 mmHg and 24-h indirect BP < 125/80 mmHg); 2) normotensive (NT) group, 84 controls matched for age and sex; 3) WHO-I group, 95 hypertensive patients with WHO stage I (office BP > or = 140/90 mmHg and 24-h BP > or = 125/80 mmHg); and 4) WHO-II group, 69 hypertensive patients with WHO stage II. Their BPc and heart rate (HR; HRc, clinic HR) values were measured by a BP-ECG monitoring device in the outpatient clinic. Power-spectral analysis was used to obtain the ratio between the low-frequency component (LF) and high-frequency component (HF) of ECG-RR variability (LF/HF = LH). Twenty-four-hour indirect BP (and BP0) and base HR (HR0) were measured by a portable device (TM2425) at 30-min intervals. Then, DeltaBPc (= BPc - BP0) was estimated by performing linear multivariate analysis applying the model equation DeltaBPc = (BPc -alphaLH)(1-betaHR0/HRc) + epsilon to the above variables (alpha and beta, constant values; epsilon, error). This model equation made it possible to estimate BP0 (and DeltaBPc) with a high coefficient of correlation (r > or = 0.85, mean of error less than 0.82 +/- 5.9 mmHg). The predictive accuracy for discrimination between WCH and sustained hypertension (WHO-I and WHO-II groups) by this equation was 88%. The new DeltaBP-estimation device (BP-ECG monitor) enabled us to infer BP0 and is therefore useful in estimating WCH in the outpatient clinic.  相似文献   
5.
6.
7.
8.
Humoral hypercalcemia of malignancy (HHM) in neoplastic syndrome has been most commonly reported in squamous cell carcinoma. Gallbladder carcinoma with HHM is uncommon. In this report, we describe a male case of gallbladder carcinoma with marked hypercalcemia and a high level of serum parathyroid hormone-related peptide (PTHrP). An immunohistochemical examination using PTHrP was also positive.  相似文献   
9.
Some physiological substances, including acetylcholine and nitric oxide, are useful candidates for stimulation of intestinal absorption of drugs. In the present study, we elucidated the ability of epinephrine (Epi) to stimulate the intestinal absorption of drugs. We evaluated the ability of Epi to enhance absorption of macromolecules using dextran (Mw 4000 Da), which is poorly absorbed from the intestine, as a model compound in situ in a closed loop of the rat jejunum. Treatment of the jejunum with Epi resulted in significant increase in absorption of dextran in a dose-dependent fashion. The area under the curve (AUC) from 0 to 4 h in the Epi-treated jejunum was 13-fold higher than that in the vehicle-treated jejunum. The absorption-enhancing activity of Epi was 40-fold higher than that of caprate, a clinically used absorption-enhancer of drugs. In the experimental conditions used in this study, histological injury of the mucosa and perturbation of the mucosal membrane were not observed in the Epi-treated jejunum. Treatment with an antagonist of alpha-adrenergic receptors attenuated the stimulation of intestinal absorption by Epi, and treatment with an agonist of alpha-adrenergic receptors resulted in enhancement of intestinal absorption. While an antagonist of beta-adrenergic receptors enhanced the absorption-enhancing effect of Epi, an agonist of beta-adrenergic receptors stimulated intestinal absorption. These results indicate that stimulation of adrenergic receptors may be a novel strategy for intestinal absorption of drugs.  相似文献   
10.
A 69‐year‐old man was admitted to Toho University Omori Medical Center complaining of icterus. Abdominal computed tomography, magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography were suspicious of cholangioma of inferior bile duct. Peroral cholangioscopy using narrow band imaging (NBI) was performed and it was possible to diagnose the mucosal spread lesions of cholangioma. Histological findings reflected the endoscopic findings. Mucosal spread lesions of cholangiocarcinoma were successfully diagnosed using the CHF‐B260 for NBI.  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