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   5376篇
  免费   400篇
  国内免费   20篇
耳鼻咽喉   32篇
儿科学   164篇
妇产科学   110篇
基础医学   842篇
口腔科学   75篇
临床医学   447篇
内科学   1481篇
皮肤病学   140篇
神经病学   538篇
特种医学   120篇
外科学   447篇
综合类   26篇
一般理论   3篇
预防医学   494篇
眼科学   112篇
药学   319篇
中国医学   41篇
肿瘤学   405篇
  2023年   79篇
  2022年   156篇
  2021年   283篇
  2020年   125篇
  2019年   182篇
  2018年   216篇
  2017年   145篇
  2016年   171篇
  2015年   196篇
  2014年   224篇
  2013年   295篇
  2012年   438篇
  2011年   470篇
  2010年   181篇
  2009年   178篇
  2008年   318篇
  2007年   264篇
  2006年   262篇
  2005年   244篇
  2004年   247篇
  2003年   210篇
  2002年   229篇
  2001年   51篇
  2000年   48篇
  1999年   54篇
  1998年   36篇
  1997年   36篇
  1996年   27篇
  1995年   23篇
  1994年   21篇
  1993年   29篇
  1992年   35篇
  1991年   26篇
  1990年   16篇
  1989年   24篇
  1988年   13篇
  1987年   14篇
  1986年   11篇
  1985年   12篇
  1984年   7篇
  1983年   6篇
  1982年   15篇
  1981年   10篇
  1980年   8篇
  1979年   9篇
  1977年   6篇
  1975年   6篇
  1968年   6篇
  1938年   8篇
  1927年   7篇
排序方式: 共有5796条查询结果,搜索用时 296 毫秒
71.
72.
73.
The general microscopic characteristics of nerves are described in several textbooks of histology, but the specific microanatomies of most nerves that can be blocked by anesthesiologists are usually less well known. Our objective was to evaluate the 3D reconstruction of nerve fascicles from optical projection tomography images (OPT) and the ability to undertake an internal navigation exploring the morphology in detail, more specifically the fascicular interconnections. Median and lingual nerve samples were obtained from five euthanized piglets. OPT images of the samples were acquired and 3D reconstruction was performed. The OPT technique revealed the inner structure of the nerves at high resolution, including large and small fascicles, perineurium, interfascicular tissue, and epineurium. The fascicles were loosely packed inside the median nerve and more densely so in the lingual nerve. Analysis of the 3D models demonstrated that the nerve fascicles can show six general spatial patterns. Fascicular interconnections were clearly identified. The 3D reconstruction of nerve fascicles from OPT images opens a new path for research into the microstructure of the inner contents of fascicular nerve groups and their spatial disposition within the nerve including their interconnections. These techniques enable 3D images of partial areas of nerves to be produced and could became an excellent tool for obtaining data concerning the 3D microanatomy of nerves, essential for better interpretation of ultrasound images in clinical practice and thus avoiding possible neurological complications. Clin. Anat. 31:424–431, 2018. © 2017 Wiley Periodicals, Inc.  相似文献   
74.
ObjectiveTo assess the occurrence of Leptospira spp serovar Hardjo among Zebu cattle in some livestock producing areas of Kaduna State, Nigeria.MethodsSera samples were obtained from 164 Zebu breed of cattle above one year osf age in seven cattle farms were screened for antibodies to Leptospira spp. serovar Hardjo using Enzyme linked immunosorbent assay (ELISA).ResultsAntibodies to Leptospira spp. serovar Hardjo were detected in eighteen (10.98%) out of the 164 animals sampled. There was no significant difference (P>0.05) in seropositivity between the different age groups or between different Zebu breeds.ConclusionThe presence of Leptospirosis among the Zebu breeds of cattle may poses a threat to livestock production and has public health implication due to its zoonotic potential.  相似文献   
75.
IRE1α is an endoplasmic reticulum (ER)-resident transmembrane signaling protein and a cellular stress sensor. The protein harbors a cytosolic dual kinase/endoribonuclease activity required for adaptive responses to micro-environmental changes. In an orthotopic xenograft model of human glioma, invalidation of IRE1α RNase or/and kinase activities generated tumors with remarkably distinct phenotypes. Contrasting with the extensive angiogenesis observed in tumors derived from control cells, the double kinase/RNase invalidation reprogrammed mesenchymal differentiation of cancer cells and produced avascular and infiltrative glioblastomas with blood vessel co-option. In comparison, selective invalidation of IRE1α RNase did not compromise tumor angiogenesis but still elicited invasive features and vessel co-option. In vitro, IRE1α RNase deficient cells were also endowed with a higher ability to migrate. Constitutive activation of both enzymes led to wild-type-like lesions. The presence of IRE1α, but not its RNase activity, is therefore required for glioblastoma neovascularization, whereas invasion results only from RNase inhibition. In this model, two key mechanisms of tumor progression and cancer cell survival are functionally linked to IRE1α.  相似文献   
76.
77.
78.
Crohn's disease (CD) is an inflammatory chronic bowel disorder; it can involve the whole gastrointestinal tract, but its localization in the ileum or colon is most common. The reference standard for the diagnosis of CD is ileocolonoscopy with histologic assessment. The reference standard for the detection of any complications is surgery. However, imaging techniques have an important role both in the detection/localization of CD and in the follow-up of CD patients. In the last few years, the technical development of ultrasound equipment, the advent of new technologies such as elastography and mostly the increased expertise of sonographers have boosted the role of bowel ultrasound in assessment of the gastrointestinal tract. In fact, bowel ultrasound is particularly attractive thanks to its widespread availability, non-invasiveness, low cost and good reproducibility, as it can be easily repeated during follow-up. The aim of this article is to provide an extensive overview of the actual role of bowel ultrasound in the detection and follow-up of patients with CD.  相似文献   
79.
80.
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