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   34359篇
  免费   2677篇
  国内免费   1397篇
耳鼻咽喉   301篇
儿科学   521篇
妇产科学   527篇
基础医学   4894篇
口腔科学   918篇
临床医学   3482篇
内科学   6020篇
皮肤病学   559篇
神经病学   2616篇
特种医学   1303篇
外国民族医学   8篇
外科学   4170篇
综合类   3463篇
现状与发展   3篇
一般理论   9篇
预防医学   2062篇
眼科学   770篇
药学   3292篇
  23篇
中国医学   882篇
肿瘤学   2610篇
  2024年   168篇
  2023年   305篇
  2022年   629篇
  2021年   853篇
  2020年   663篇
  2019年   685篇
  2018年   903篇
  2017年   794篇
  2016年   696篇
  2015年   929篇
  2014年   1114篇
  2013年   1213篇
  2012年   1746篇
  2011年   1776篇
  2010年   1098篇
  2009年   948篇
  2008年   1409篇
  2007年   1515篇
  2006年   1397篇
  2005年   1267篇
  2004年   1019篇
  2003年   899篇
  2002年   787篇
  2001年   2030篇
  2000年   1930篇
  1999年   1673篇
  1998年   662篇
  1997年   494篇
  1996年   351篇
  1995年   310篇
  1994年   277篇
  1993年   218篇
  1992年   869篇
  1991年   744篇
  1990年   685篇
  1989年   735篇
  1988年   654篇
  1987年   604篇
  1986年   573篇
  1985年   507篇
  1984年   321篇
  1983年   254篇
  1982年   153篇
  1981年   112篇
  1980年   90篇
  1979年   170篇
  1973年   72篇
  1972年   74篇
  1971年   76篇
  1970年   67篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Yang  Luo-Ping  Gu  Xiao-Long  Chen  Jin-Xiang  Yang  Jie  Tan  Sui-Yi  Duan  Wen-Jun 《Journal of natural medicines》2018,72(3):808-815
Journal of Natural Medicines - Two new dyhydrophaseic acid glucoside isomers, (1′S, 3′R, 5′S, 8′R, 2Z, 4E)-dihydrophaseic acid-3′-O-β-d-glucopyranoside (2) and...  相似文献   
2.
群体感应系统(quorum sensing system, QS)是一种微生物细胞与细胞间的交流系统。铜绿假单胞菌是该系统的典型代表,可调控细菌产生对抗生素的耐药、形成生物膜、产生毒力因子,并且减弱宿主的免疫应答。群体感应系统抑制剂(quorum sensing inhibitors, QSIs)在不影响细菌生长的前提下可降低细菌的毒性,且增强细菌生物膜对抗生素治疗的敏感性,这些特点使QSIs成为目前抗感染领域的研发热点。本文就铜绿假单胞菌的群体感应系统及QSIs的研究进展进行了综述。  相似文献   
3.
4.
5.
Inflammation Research - Although some glycolytic intermediates have been shown to modulate several cell type formation and activation, the functional role of fructose 1,6-bisphosphate (FBP) on...  相似文献   
6.
International Journal of Clinical Pharmacy - Background Patients requiring SLED are often critically ill and/or hemodynamically unstable, and often need antibiotic therapy for life-threatening...  相似文献   
7.

Objectives

We aimed to evaluate the relationship between baseline renal function and changes in telomere length in Han Chinese.

Methods

The telomere restriction fragment (TRF) length of leukocytes in the peripheral blood was measured in healthy volunteers recruited in 2014. The estimated glomerular filtration rate (eGFR) was calculated based on serum creatinine (Scr) and serum cystatin C (CysC)-eGFRcys and eGFRScr-cys through the Cockcroft-Gault formula (eGFRC-G) or the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI / eGFRCKD-EPI) equation. The correlation between telomere length changes over time and renal function was analyzed.

Results

Leukocyte TRF lengths were negatively correlated to age (r = -0.393, p < 0.001) and serum CysC (r = -0.180, p < 0.01), while positively associated with eGFRCKD-EPI, eGFRC-G, eGFRcys, and eGFRScr-cys (r = 0.182, 0.122, 0.290, and 0.254 respectively, p < 0.01). The 3-year change of telomere length was 46 bp/years. When adjusted for age, the associations between telomere length changes and baseline, subsequent TRF lengths, and serum CysC were no longer present. No association was observed between TRF length changes and renal function.

Conclusion

The rate of telomere length changes was affected by age and baseline telomere length. The telomere length changes might be important markers for aging.
  相似文献   
8.
Offshore oil exploration creates threats to coastal ecosystems, including increasing urbanization and associated effluent releases. Genotoxicity biomarkers in mussels were determined across a gradient of coastal zone influences of offshore petroleum exploration in southeastern Brazil. Coastal ecosystems such as estuaries, beaches and islands were seasonally monitored for genotoxicity evaluation using the brown mussel Perna perna. The greatest DNA damage (5.2%?±?1.9% tail DNA and 1.5‰? ±?0.8‰ MN) were observed in urban estuaries, while Santana Archipelago showed levels of genotoxicity near zero and is considered a reference site. Mussels from urban and pristine beaches showed intermediate damage levels, but were also influenced by urbanization. Thus, mussel genotoxicity biomarkers greatly indicated the proposed oil exploration and urbanization scenarios that consequently are genetically affecting coastal organisms.  相似文献   
9.
舌大小与开He相关性的研究   总被引:6,自引:0,他引:6  
目的 研究舌大小与开He之间的关系。方法 采用B型超声成像方法分别测量正常He与开He患者的舌大小,通过牙He与正常He舌大小的比较,研究舌大小与开He的相关性。结果 开He患者的舌大小测量结果均值大于正常He者,而且这种差别有显著的统计学意义。结论 与正常He者比较,开He患者存在舌过大的特性。  相似文献   
10.
In order to understand the pathogenesis of gastric lymphoma, we investigated the association of H.pylori infection with lymphoid follicular hyperplasia. Eighty-four gastric specimens removed for gastroduodenal ulcer were histologically examined. The distribution and prevalence of H. pylori, neutrophilic and lymphocytic infiltration, mucosal atrophy, intestinal metaplasia, and lymphoid follicles were scored. The lymphoid follicles were more frequently observed in H.pylori positive cases. They indicated a positive correlation with the score of H. pylori. When follicular gastritis (FG) was defined as a case in which the secondary lymphoid follicles (Lf2) numbered two or more per one centimeter of mucosa in the pyloric gland area of the lesser curvature, twenty specimens out of the 84 (24%) fit that definition. All of the FG cases were H.pylori positive, and they displayed high H. pylori scores. It was supposed that most FG cases would ultimately lead to atrophic gastritis, whereas H.pylori would gradationally decrease or disappear in accordance with the aging and progression of intestinal metaplasia. The histological features of the FG cases, however, were similar to the background mucosal state of early-stage MALT-type gastric lymphoma. We may conclude that H. pylori infection is one cause of the FG, which may be a high-risk condition that gives rise to MALT-type gastric lymphoma.  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