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   3163篇
  免费   168篇
  国内免费   16篇
耳鼻咽喉   51篇
儿科学   89篇
妇产科学   57篇
基础医学   347篇
口腔科学   136篇
临床医学   237篇
内科学   784篇
皮肤病学   16篇
神经病学   341篇
特种医学   169篇
外科学   474篇
综合类   6篇
预防医学   124篇
眼科学   31篇
药学   195篇
中国医学   6篇
肿瘤学   284篇
  2023年   24篇
  2022年   46篇
  2021年   82篇
  2020年   57篇
  2019年   89篇
  2018年   79篇
  2017年   66篇
  2016年   79篇
  2015年   83篇
  2014年   105篇
  2013年   163篇
  2012年   280篇
  2011年   208篇
  2010年   151篇
  2009年   129篇
  2008年   214篇
  2007年   197篇
  2006年   196篇
  2005年   218篇
  2004年   204篇
  2003年   181篇
  2002年   155篇
  2001年   18篇
  2000年   23篇
  1999年   24篇
  1998年   24篇
  1997年   36篇
  1996年   24篇
  1995年   19篇
  1994年   28篇
  1993年   21篇
  1992年   12篇
  1991年   14篇
  1990年   7篇
  1989年   6篇
  1988年   11篇
  1987年   3篇
  1986年   4篇
  1985年   10篇
  1984年   6篇
  1983年   11篇
  1982年   5篇
  1980年   2篇
  1977年   3篇
  1973年   2篇
  1967年   2篇
  1942年   2篇
  1928年   3篇
  1905年   2篇
  1902年   2篇
排序方式: 共有3347条查询结果,搜索用时 62 毫秒
61.
We report on oxygenation changes noninvasively recorded by multichannel continuous-wave near infrared spectroscopy (CW-NIRS) during endovascular neuroradiologic interventions requiring temporary balloon occlusion of arteries supplying the cerebral circulation. Digital subtraction angiography (DSA) provides reference data on the site, timing, and effectiveness of the flow stagnation as well as on the amount and direction of collateral circulation. This setting allows us to relate CW-NIRS findings to brain specific perfusion changes. We focused our analysis on the transition from normal perfusion to vessel occlusion, i.e., before hypoxia becomes clinically apparent. The localization of the maximal response correlated either with the core (occlusion of the middle cerebral artery) or with the watershed areas (occlusion of the internal carotid artery) of the respective vascular territories. In one patient with clinically and angiographically confirmed insufficient collateral flow during carotid artery occlusion, the total hemoglobin concentration became significantly asymmetric, with decreased values in the ipsilateral watershed area and contralaterally increased values. Multichannel CW-NIRS monitoring might serve as an objective and early predictive marker of critical perfusion changes during interventions—to prevent hypoxic damage of the brain. It also might provide valuable human reference data on oxygenation changes as they typically occur during acute stroke.  相似文献   
62.
63.
This study: (i) investigated the in vitro cytotoxicity and mode of action of lurbinectedin (PM01183) and Zalypsis® (PM00104) compared with trabectedin in cell lines deficient in specific mechanisms of repair, (ii) evaluated their in vivo antitumor activity against a series of murine tumors and human xenografts. The antiproliferative activity, the DNA damage and the cell cycle perturbations induced by the three compounds on tumor lines were very similar. Nucleotide Excision Repair (NER) deficient cells were approximately fourfold more resistant to trabectedin, lurbinectedin and Zalypsis®. Cells deficient in non‐homologous end joining (NHEJ), MRN complex and translesion synthesis (TLS) were slightly more sensitive to the three compounds (approximately fivefold) while cells deficient in homologous recombination (HR) were markedly more sensitive (150–200‐fold). All three compounds showed a good antitumor activity in several in vivo models. Lurbinectedin and trabectedin had a similar pattern of antitumor activity in murine tumors and in xenografts, whereas Zalypsis® appeared to have a distinct spectrum of activity. The fact that no relationship whatsoever was found between the in vitro cytotoxic potency and the in vivo antitumor activity, suggests that in addition to direct cytotoxic mechanisms other host‐mediated effects are involved in the in vivo pharmacological effects.  相似文献   
64.
Current perspectives in therapeutic myocardial angiogenesis   总被引:2,自引:0,他引:2  
The complex mechanisms mediating the development of new blood vessels are now beginning to be unraveled. In conjunction with major biotechnology advances, this has facilitated the initiation of translational research related to a novel treatment strategy for patients with myocardial or leg ischemia due to obstructive arterial disease--therapeutic angiogenesis. At present, at least 17 clinical trials of myocardial angiogenesis have been presented involving over 900 patients. Uncertainty exists as to the optimal delivery route and angiogenic agent, and this uncertainty is reflected in the diverse methodology of the trials published thus far. The majority of patients received an angiogenic protein via the intracoronary route. Other delivery techniques--such as direct intramyocardial injection via transepicardial or transendocardial routes--and other angiogenic agents, including master genes, have also been studied. Most recently, interest has grown in the potential angiogenesis effects of cell therapy--such as autologous bone marrow cells or cultured stem cells--and there are now several groups initiating Phase I/II trials in this area. This review summarizes the current evidence pertaining to the safety, feasibility, and efficacy of various angiogenic techniques aimed at enhancing myocardial blood flow and alleviating angina.  相似文献   
65.
66.
67.
68.
69.
70.

Background

Damage to the cardiac conduction system requiring permanent pacemaker (PPM) implantation is a known adverse outcome of transcatheter aortic valve replacement (TAVR). A permanent-temporary pacemaker (PTPM) is a device that involves an active-fixation lead attached to an external pulse generator taped to the skin. We reviewed the utility of PTPMs as a temporary bridge measure after TAVR in patients with conduction abnormalities that do not meet conventional criteria for PPM placement.

Methods

Between January 01, 2013 and December 31, 2015, we analyzed 67 patients who received PTPM after TAVR. Baseline demographics, comorbidities, type and size of the valve, pre-TAVR electrocardiograms (ECGs), post-TAVR ECGs at 1 day, 1 month, and 6 months, and pacemaker interrogation results were reviewed for each patient if available.

Results

The mean age of patients was 80.5?±?9.1 years. PTPM were placed for 2.3?±?2.4 days. Among these patients, 44.8% (n?=?30) received a PPM prior to discharge. Male gender (OR 2.84, 95% CI 1.05–7.69, p?=?0.05) and an increase in QRS duration post-TAVR (p?=?0.01) were associated with PPM placement. Pacemaker interrogation data of 11 patients with PPM revealed that 27% (n?=?3) had <?1% V-pacing requirements and <?10% A-pacing requirements.

Conclusions

In post-TAVR patients who develop conduction abnormalities that do not meet conventional PPM implantation indications, PTPM safely provides a time period for further assessment and may prevent unnecessary PPM implantation. Male gender and an increase in QRS duration post-TAVR are associated with PPM implantation. Additionally, some patients may recover from their conduction disturbances and demonstrate low pacemaker utilization.
  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