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   11262篇
  免费   603篇
  国内免费   110篇
耳鼻咽喉   112篇
儿科学   208篇
妇产科学   132篇
基础医学   1269篇
口腔科学   145篇
临床医学   760篇
内科学   3240篇
皮肤病学   191篇
神经病学   759篇
特种医学   340篇
外科学   2209篇
综合类   69篇
预防医学   307篇
眼科学   131篇
药学   697篇
中国医学   33篇
肿瘤学   1373篇
  2024年   8篇
  2023年   112篇
  2022年   221篇
  2021年   362篇
  2020年   207篇
  2019年   274篇
  2018年   367篇
  2017年   214篇
  2016年   338篇
  2015年   345篇
  2014年   420篇
  2013年   480篇
  2012年   857篇
  2011年   892篇
  2010年   474篇
  2009年   389篇
  2008年   724篇
  2007年   789篇
  2006年   713篇
  2005年   727篇
  2004年   660篇
  2003年   544篇
  2002年   619篇
  2001年   113篇
  2000年   87篇
  1999年   97篇
  1998年   105篇
  1997年   106篇
  1996年   77篇
  1995年   70篇
  1994年   77篇
  1993年   57篇
  1992年   41篇
  1991年   42篇
  1990年   31篇
  1989年   30篇
  1988年   39篇
  1987年   30篇
  1986年   25篇
  1985年   27篇
  1984年   30篇
  1983年   25篇
  1982年   12篇
  1981年   22篇
  1980年   15篇
  1977年   14篇
  1975年   7篇
  1974年   8篇
  1973年   8篇
  1971年   7篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
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   
4.
5.
6.
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   
7.
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   
8.
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   
9.
Two successful cases of the surgical treatment for coronary artery aneurysm (non-Kawasaki disease) were reported. The first case had a saccular aneurysm on the left circumflex coronary artery (LCx) #14. Resection of the LCx aneurysm was performed subsequent to single vessel coronary artery bypass grafting (CABG) to the distal portion of LCx#14 under the cardioplegic cardiac arrest. The second case had aneurysms on both the left anterior descending artery (LAD) #7 (fusiform) and the LCx#11 (saccular). After double vessel CABG to LAD#7 and LCx#11, ligation or resection of two aneurysms was performed successfully. Postoperative courses have been uneventful with good angiographic results achieved. Since these surgical procedures demonstrated safety, the patients are expected to achieve a good long-term prognosis.  相似文献   
10.
The proportion of T-lymphocyte subsets of the regional lymph node lymphocytes of 36 gastric cancer patients was analysed using single and two color flow cytometry technique. The antibodies against human T-lymphocyte were anti-CD3, CD4, CD8, CD4 X Leu8, CD4 X 4B4 and CD8 X CD11. The results were as follows. 1) Using single color analysis, the proportion of CD3+ and CD4+ cells in the metastatic lymph node was decreased and that of CD8+ cells was not changed compared with the non-metastatic lymph node. Therefore, the ratio of CD4 to CD8 was reduced. Using two color analysis, proportion of CD4+ Leu8- cells and CD4+ 4B4- cells was reduced. On the contrary, that of CD8+ CD11+ cells was increased in the metastatic lymph node compared with the non-metastatic lymph node. 2) The proportion of CD3+, CD4+ and CD4+ 4B4- cells was decreased in the non-metastatic lymph node of patients with lymph node metastasis compared with that of patients without lymph node metastasis. 3) The proportion of T-lymphocyte subsets was not changed in the metastatic lymph node, whether the volume including cancer cell is much or not. These results suggest that the metastatic lymph node was less defensive against lymph node metastasis in the gastric cancer.  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