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   809篇
  免费   62篇
  国内免费   25篇
耳鼻咽喉   2篇
儿科学   19篇
妇产科学   15篇
基础医学   77篇
口腔科学   15篇
临床医学   129篇
内科学   168篇
皮肤病学   31篇
神经病学   47篇
特种医学   103篇
外科学   91篇
综合类   37篇
预防医学   63篇
眼科学   1篇
药学   73篇
肿瘤学   25篇
  2023年   3篇
  2021年   4篇
  2020年   8篇
  2019年   14篇
  2018年   13篇
  2017年   4篇
  2016年   6篇
  2015年   17篇
  2014年   17篇
  2013年   29篇
  2012年   61篇
  2011年   32篇
  2010年   26篇
  2009年   38篇
  2008年   35篇
  2007年   33篇
  2006年   30篇
  2005年   28篇
  2004年   24篇
  2003年   28篇
  2002年   25篇
  2001年   25篇
  2000年   21篇
  1999年   24篇
  1998年   28篇
  1997年   22篇
  1996年   33篇
  1995年   13篇
  1994年   24篇
  1993年   12篇
  1992年   12篇
  1991年   14篇
  1990年   17篇
  1989年   14篇
  1988年   29篇
  1987年   21篇
  1986年   19篇
  1985年   22篇
  1984年   11篇
  1983年   7篇
  1982年   7篇
  1981年   6篇
  1980年   6篇
  1979年   2篇
  1978年   7篇
  1977年   4篇
  1976年   8篇
  1975年   5篇
  1968年   3篇
  1965年   1篇
排序方式: 共有896条查询结果,搜索用时 15 毫秒
81.
The molting cycle of the freshwater crayfish, Procambarus clarkii, has been used as a model to study the cellular physiology and molecular biology of Ca "supply" proteins that effect transcellular vectorial Ca(2+) movement to achieve organismal Ca homeostasis. Specifically, periods of net Ca(2+) influx (postmolt) have been compared with periods of net Ca(2+) balance (intermolt). The broader goal is to understand the paradox facing epithelial cells of maintaining low cytosolic Ca(2+)in the face of mass Ca(2+)transit across epithelial cells. This mini-review compares mRNA and protein expression profiles for a series of proteins that are of strategic importance in effecting transcellular Ca(2+) flux in a selected epithelium, the antennal gland (kidney analog) specifically during apical to basolateral Ca(2+) conveyance. Target proteins were selected as representative of key "stages" in the transcellular transfer of Ca(2+): import (epithelial Ca(2+) channel, ECaC); storage (sarco/endoplasmic reticulum Ca(2+) ATPase, SERCA); buffering (sarcoplasmic Ca(2+) binding protein, SCP); and export (plasma membrane Ca(2+) ATPase, PMCA and Na(+)/Ca(2+) exchanger, NCX). The purpose of this review is to assess coordination of expression of these target proteins at times of high Ca(2+) demand (premolt and postmolt) compared to low Ca demand (intermolt) as a function of cellular location (apical vs. basolateral; endomembranes vs. plasma membranes) and relative abundance within different regions of the antennal gland. Understanding the spatiotemporal regulation of Ca(2+) handling proteins involved in transcellular transport is fundamental to investigating their endocrine regulation.  相似文献   
82.
The polyomaviruses KI (KIPyV) and WU (WUPyV) have recently been discovered in specimens from patients with respiratory tract infections. To analyze the frequency and clinical impact in a cohort of pediatric patients in a German University Children’s Hospital. Nasopharyngeal aspirates or bronchoalveolar lavage specimens of 229 children with acute respiratory tract infection were screened for KIPyV and WUPyV using polymerase chain reaction-based methods. KIPyV was detected in 2 (0.9%) and WUPyV in 1 (0.4%) patients, without co-infections with other respiratory viruses but with co-detection of CMV, EBV and HHV 6 in one immunocompromised patient. Only a very small proportion (1.3%) of positive samples for KIPyV and WUPyV was documented in this study; the clinical relevance of these viruses remains unclear and requires further evaluation.  相似文献   
83.
84.
85.
86.
Background Non‐ablative 1550‐nm erbium‐doped fractional photothermolysis systems (FPS) and 10 600‐nm carbon dioxide fractional laser systems (CO2 FS) have been effectively used to treat scars. Objective We compared the efficacy and safety of single‐session treatments of FPS and CO2 FS for acne scars through a randomized, split‐face, evaluator‐blinded study. Methods Eight patients with acne scars were enrolled in this study. Half of each subject’s face was treated with FPS and the other half was treated with CO2 FS. We used a quartile grading scale for evaluations. Results At 3 months after the treatment, the mean grade of improvement based on clinical assessment was 2.0 ± 0.5 for FPS and 2.5 ± 0.8 for CO2 FS. On each side treated by FPS and CO2 FS, the mean duration of post‐therapy crusting and scaling was 2.3 and 7.4 days respectively and that of post‐therapy erythema was 7.5 and 11.5 days respectively. The mean VAS pain score was 3.9 ± 2.0 with the FPS and 7.0 ± 2.0 with the CO2 FS. Conclusion We demonstrated the efficacy and safety of single‐session acne scar treatment using FPS and CO2 FS in East Asian patients. We believe that our study could be used as an essential reference when choosing laser modalities for scar treatment.  相似文献   
87.
88.
89.
90.
Tagged MR imaging in a deforming phantom: photographic validation   总被引:1,自引:0,他引:1  
Moore  CC; Reeder  SB; McVeigh  ER 《Radiology》1994,190(3):765
  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