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   521篇
  免费   32篇
耳鼻咽喉   5篇
儿科学   14篇
妇产科学   9篇
基础医学   45篇
口腔科学   5篇
临床医学   35篇
内科学   135篇
皮肤病学   20篇
神经病学   26篇
特种医学   22篇
外科学   104篇
综合类   3篇
预防医学   23篇
眼科学   4篇
药学   58篇
中国医学   8篇
肿瘤学   37篇
  2023年   8篇
  2022年   7篇
  2021年   22篇
  2020年   8篇
  2019年   19篇
  2018年   19篇
  2017年   13篇
  2016年   10篇
  2015年   11篇
  2014年   12篇
  2013年   15篇
  2012年   20篇
  2011年   20篇
  2010年   10篇
  2009年   16篇
  2008年   20篇
  2007年   30篇
  2006年   25篇
  2005年   23篇
  2004年   25篇
  2003年   20篇
  2002年   31篇
  2001年   11篇
  2000年   10篇
  1999年   8篇
  1998年   8篇
  1996年   5篇
  1995年   3篇
  1994年   3篇
  1993年   4篇
  1992年   7篇
  1991年   9篇
  1990年   8篇
  1989年   10篇
  1988年   13篇
  1987年   12篇
  1986年   15篇
  1985年   10篇
  1984年   6篇
  1983年   2篇
  1979年   4篇
  1974年   2篇
  1969年   1篇
  1968年   1篇
  1967年   2篇
  1966年   1篇
  1963年   1篇
  1961年   1篇
  1954年   1篇
  1935年   1篇
排序方式: 共有553条查询结果,搜索用时 15 毫秒
41.
The effect of estrogen (17 beta-estradiol; E2) replacement on the liver function was examined in ovariectomized rats. Ovariectomy decreased serum transaminase activity and physiological dosage levels of E2 replacement returned the activity up to or above non-ovariectomized levels. Under the conditions of this experiment the elevated serum transaminase levels in the E2 replacement were not coincident with histological changes suggestive of liver dysfunction. The elevations of both serum glutamic oxaloacetic transaminase (GOT) and serum mitochondrial GOT were accompanied by increased hepatic tissue activity, suggesting that the elevated serum levels can be attributed to the accelerated synthesis of the enzymes. On the other hand, the elevation of serum glutamic pyruvic transaminase was not accompanied by increased tissue activity in the original organs, namely liver, kidney, heart and skeletal muscle. Ovariectomy decreased serum albumin and inhibited development of rough endoplasmic reticulum in the liver, and E2 replacement returned them up to or above the non-ovariectomized levels.  相似文献   
42.
The aim of this study was to evaluate ventricular dysfunction using the longitudinal strain analysis in 4-chamber (4CH) cine MR imaging, and to investigate the agreement between the semi-automatic and manual measurements in the analysis. Fifty-two consecutive patients with ischemic, or non-ischemic cardiomyopathy and repaired tetralogy of Fallot who underwent cardiac MR examination incorporating cine MR imaging were retrospectively enrolled. The LV and RV longitudinal strain values were obtained by semi-automatically and manually. Receiver operating characteristic (ROC) analysis was performed to determine the optimal cutoff of the minimum longitudinal strain value for the detection of patients with cardiac dysfunction. The correlations between manual and semi-automatic measurements for LV and RV walls were analyzed by Pearson coefficient analysis. ROC analysis demonstrated the optimal cut-off of the minimum longitudinal strain values (εL_min) for diagnoses the LV and RV dysfunction at a high accuracy (LV εL_min = ?7.8 %: area under the curve, 0.89; sensitivity, 83 %; specificity, 91 %, RV εL_min = ?15.7 %: area under the curve, 0.82; sensitivity, 92 %; specificity, 68 %). Excellent correlations between manual and semi-automatic measurements for LV and RV free wall were observed (LV, r = 0.97, p < 0.01; RV, r = 0.79, p < 0.01). Our semi-automatic longitudinal strain analysis in 4CH cine MR imaging can evaluate LV and RV dysfunction with simply and easy measurements. The strain analysis could have extensive application in cardiac imaging for various clinical cases.  相似文献   
43.

Introduction

We previously demonstrated that in utero vesicoamniotic shunting of obstructive uropathy in fetal lambs produces a shrunken noncompliant bladder. We hypothesized that the normal fetal bladder filling and emptying cycle in fetal life is critical to the development of normal bladder function.

Materials and Methods

We placed vesicoamniotic shunts in 4 normal fetal lambs at 74 days' gestation. The fetuses were delivered at term (145 days), and bladder volume and compliance were measured and compared with those measurements in 3 normal term fetuses. The lambs were then killed and the renal tracts and bladders removed submitted to histologic examination.

Results

All shunted lambs survived to term. Three normal control lambs were delivered at term. The mean bladder volume in shunted lambs was 4 ± 2.8 mL (n = 4) compared with 60 ± 17 mL (n = 3) in control lambs (P < .05). Bladders in the shunted lambs had very poor compliance compared with normal lambs' bladders. Histologic examination of the shunted bladders showed increased fibrosis and distortion of the muscle layers compared with control bladders.

Conclusion

Even in the absence of obstruction, preventing normal bladder filling and emptying in fetal life produces fibrotic bladders with poor compliance.  相似文献   
44.
45.
46.
47.
Animal cells contain two populations of microtubules: one radiating from the centrosome and the other growing from non‐centrosomal sites. Whether or not they have differing roles in cellular architecture and function remains not fully understood. The cytoplasmic protein Nezha (also known as CAMSAP3) stabilizes non‐centrosomal microtubules by attaching to their minus ends. Here, we found that depletion of CAMSAP3 in HeLa cells resulted in a relative increase in centrosomal microtubules, and this change was accompanied by accelerated actin stress fiber formation. In these cells, RhoA activity was upregulated, and the soluble fraction of GEF‐H1, a RhoGEF whose activity is inhibited by binding to microtubules, increased, explaining why stress fiber formation was promoted. We further found that CAMSAP3 depletion led to an increase in detyrosinated microtubules, and these microtubules did not interact with GEF‐H1. These findings suggest that CAMSAP3‐anchored non‐centrosomal microtubules capture GEF‐H1 more efficiently than other microtubules do and that a balance between these microtubules is important to maintain proper actin organization.  相似文献   
48.

Purpose  

The purpose of this study is to propose a novel method to depict small calcifications in ultrasound B-mode images using decorrelation of forward scattered waves with no decrease in the frame rate.  相似文献   
49.
A 53-year-old male was admitted to our hospital complaining of high fever with chillness, cough and dyspnea after traveling to Arizona in the United States. The chest X-ray films taken on admission showed consolidation in the right middle lung field and bilateral nodular shadows. The laboratory data revealed an increase in white blood cell counts with eosinophilia, and a rise in erythrocyte sediment rate and serum C-reactive protein. The biopsied lung specimen by video-assisted thoracoscopic surgery showed granulomatous inflammation consisting of eosinophils and giant cells. In addition, typical spherules filled with endopores were detected in the specimen. The diagnosis of primary pulmonary coccidioidomycosis was made. After the treatment of a three months' regimen with itraconazole at the daily dosage of 200 mg, the patient's symptoms, laboratory data and radiological findings markedly improved.  相似文献   
50.
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