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   1276886篇
  免费   92759篇
  国内免费   1987篇
耳鼻咽喉   18188篇
儿科学   42269篇
妇产科学   37824篇
基础医学   187020篇
口腔科学   35395篇
临床医学   108129篇
内科学   251502篇
皮肤病学   26504篇
神经病学   99179篇
特种医学   49987篇
外国民族医学   368篇
外科学   197679篇
综合类   26526篇
现状与发展   1篇
一般理论   300篇
预防医学   92601篇
眼科学   29067篇
药学   97782篇
  1篇
中国医学   2496篇
肿瘤学   68814篇
  2018年   11827篇
  2015年   11621篇
  2014年   16003篇
  2013年   24360篇
  2012年   33566篇
  2011年   35966篇
  2010年   21222篇
  2009年   20026篇
  2008年   35000篇
  2007年   37956篇
  2006年   38513篇
  2005年   37804篇
  2004年   36387篇
  2003年   35374篇
  2002年   34923篇
  2001年   58104篇
  2000年   59591篇
  1999年   50694篇
  1998年   14240篇
  1997年   12810篇
  1996年   13072篇
  1995年   12346篇
  1994年   11758篇
  1993年   10860篇
  1992年   40986篇
  1991年   40359篇
  1990年   39889篇
  1989年   38708篇
  1988年   36110篇
  1987年   35349篇
  1986年   33724篇
  1985年   32136篇
  1984年   23924篇
  1983年   20818篇
  1982年   12377篇
  1981年   10928篇
  1980年   10204篇
  1979年   22637篇
  1978年   15877篇
  1977年   13731篇
  1976年   12970篇
  1975年   14203篇
  1974年   16684篇
  1973年   16076篇
  1972年   15319篇
  1971年   14229篇
  1970年   13215篇
  1969年   12731篇
  1968年   11978篇
  1967年   10478篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
102.
Background The appearance of eosinophils is a hallmark sign of the allergic late-phase response (LPR). Eosinophil cationic protein (ECP), a readily measurable product released from activated eosinophils, has so far not been evaluated in the ocular LPR. Objective Two sets of trials were performed in order to investigate changes of local and systemic eosinophil activity and their possible link with symptoms and hyper-reactivity in the allergic LPR in the eye. Methods In the first experiment, ECP was analysed in tears and serum and the clinical reaction was evaluated during a 72-h time–course after a single, high-dose allergen challenge out of season in one eye of 15 pollen-sensitized volunteers. In a second experiment, the hypothesis of an increased clinical response to an allergen challenge in an eye that had been provoked with allergen 48h previously was tested in nine sensitized individuals. Results In the first experiment, symptoms at 10 min and 2, 4, 6, 8 and 24 h significantly exceeded base line scores of the challenged eyes. Tear ECP was significantly elevated in challenged eyes compared to contralateral eyes at 6, 8 and 24 h. In addition, symptoms and ECP release correlated significantly at the 24-h evaluation. Serum ECP remained unchanged throughout the study period. In the second experiment, conjunctival hyperreactivity 48h after an allergen challenge was not confirmed. Conclusion ECP secretion occurs in the experimental ocular LPR and is in part associated with the magnitude of the clinical reaction, which suggests a truly pathogenic role of the activated eosinophil in pollen-induced allergic conjunctivitis.  相似文献   
103.
104.
105.
106.
107.
108.
109.
Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms.  相似文献   
110.
From 1979 to 1987, 907 patients with non-oat cell carcinoma of the lung were subjected to thoracotomy: of these, 685 (75.5%) underwent radical resection of the lung tumour. The 230 stage IIIa patients were studied in this paper. These were divided into three groups. First group: 93 patients with only local parietal or mediastinal spread without involvement of the mediastinal lymph nodes (T3N0-1M0); the 5-year survival of this group was 35% (44.1% when the ribs and muscles were not affected). A second group of 118 patients had tumour spreading to the mediastinal lymph nodes, but without local involvement (T1-2N2M0): this group had a 5-year survival of 22.3%. The 5-year survival was better in patients without metastases in the subcarinal lymph nodes than in patients with them (23.76% versus 12.89%). Skipping of lymphatic levels was frequent: 37% of patients with metastasis to mediastinal lymph nodes did not have metastases in the lymph nodes of the lung; 10% of tumours removed by lobectomy had metastases in the lymph nodes of the residual lobe. The third group with parietal and lymphatic mediastinal invasion (T3N2M0) had a poor survival (13.5% at 5 years). The author concludes that it is possible to achieve an acceptable 5-year survival in selected cases with metastasis to mediastinal lymph nodes: when the CT scan demonstrated mediastinal lymph nodes larger than 1.5 cm, mediastinoscopy was carried out and, if positive, the patient was judged inoperable.  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