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   4872篇
  免费   450篇
  国内免费   175篇
耳鼻咽喉   47篇
儿科学   126篇
妇产科学   70篇
基础医学   687篇
口腔科学   139篇
临床医学   513篇
内科学   825篇
皮肤病学   95篇
神经病学   335篇
特种医学   162篇
外国民族医学   1篇
外科学   531篇
综合类   333篇
现状与发展   1篇
预防医学   373篇
眼科学   132篇
药学   456篇
  1篇
中国医学   82篇
肿瘤学   588篇
  2023年   74篇
  2022年   204篇
  2021年   219篇
  2020年   149篇
  2019年   197篇
  2018年   179篇
  2017年   160篇
  2016年   175篇
  2015年   201篇
  2014年   233篇
  2013年   262篇
  2012年   333篇
  2011年   347篇
  2010年   185篇
  2009年   163篇
  2008年   246篇
  2007年   288篇
  2006年   232篇
  2005年   270篇
  2004年   202篇
  2003年   169篇
  2002年   152篇
  2001年   102篇
  2000年   95篇
  1999年   82篇
  1998年   42篇
  1997年   52篇
  1996年   36篇
  1995年   33篇
  1994年   33篇
  1993年   33篇
  1992年   44篇
  1991年   52篇
  1990年   32篇
  1989年   25篇
  1988年   31篇
  1987年   24篇
  1986年   21篇
  1985年   15篇
  1984年   8篇
  1982年   5篇
  1981年   5篇
  1979年   7篇
  1976年   4篇
  1974年   5篇
  1972年   8篇
  1970年   8篇
  1969年   8篇
  1966年   3篇
  1939年   4篇
排序方式: 共有5497条查询结果,搜索用时 15 毫秒
81.
82.
83.
Influenza vaccination is recommended for all health care personnel (HCP), but immunization rates for this group continue to be suboptimal. This study explores relationships between individual characteristics, beliefs, knowledge, attitudes, and vaccination behavior through 2 surveys conducted at a university health center. The findings suggest that HCP who were vaccinated the year before, intended to be vaccinated next year, believed influenza vaccination was important, and were more knowledgeable are more likely to receive a vaccine.  相似文献   
84.
The anti-anginal effects of allopurinol were assessed in experimental model rats of angina and their effects were evaluated with amlodipine. In the vasopressin-induced angina model, oral administration of allopurinol in dose of 10 mg/kg revealed remarkably analogous effects in comparison with amlodipine such as dose-dependent suppression of vasopressin-triggered time, duration and severity of ST depression. In addition, allopurinol produced dose dependent suppression of plasma Malondialdehyde (MDA) level, systolic blood pressure, cardiac contractility and cardiac oxygen consumption; while in contrast, amlodipine minimally suppressed the elevation of plasma MDA level. Endothelial NO synthase (eNOS) expression, serum nitrate were strikingly increased, however lipid profile was significantly reduced. Seemingly, allopurinol was found to be more potent than amlodipine – a calcium channel antagonist. To conclude, it was explicitly observed and verified that on the ischemic electrocardiography (ECG) changes in angina pectoris model in rats, allopurinol exerts a significant protective effects, reminiscent of enhancement of vascular oxidative stress, function of endothelial cells, improved coronary blood flow in addition to the potential enhancement in myocardial stress. Moreover, our findings were in conformity with several human studies.  相似文献   
85.
It was aimed to investigate the compressibility, compactibility, powder flow and tablet disintegration of a new excipient comprising magnesium (Mg) silicate co-processed (5%–85% w/w) onto chitin, microcrystalline cellulose (MCC) and starch as the hydrophilic polymers of interest. Initially, the mechanism of tablet disintegration was studied by measuring water infiltration rate, moisture sorption, swelling capacity and hydration ability. Moreover, the powders compression behavior was carried out by applying Kawakita model of compression analysis in addition to porosity and radial tensile strength measurements. In vitro drug release of compacts made of 400?mg ibuprofen and 300?mg of the hydrophilic polymers containing 30% w/w Mg silicate co-precipitate was investigated in phosphate buffer (pH 7.8). This work demonstrated that the incorporation of Mg silicate to the hydrophilic polymers lead to the improvement of powder flowability, compactibility, stability (with regard to storage conditions), compacts crushing strength, and disintegration time in addition to faster drug release. The overall findings are practically advantageous in the context of finding a low cost and multifunctional co-processed excipient of natural origins.  相似文献   
86.
Histiocytoses, including Langerhans cell histiocytosis (LCH), juvenile or adult xanthogranuloma (AXG) and Rosai–Dorfman disease (RDD), are rare disorders characterized by the proliferation of cells derived from monocyte/macrophage lineages. A few cases of LCH coexisting with xanthogranuloma or RDD have been reported. The etiology of these diseases remains unclear. However, oncogenic BRAFV600E mutations have been identified in LCH. Here, we report the case of a 26‐year‐old Japanese man with a 3‐month history of a solitary occipital nodule. No abnormality was detected in his other organs, and a total resection of the nodule was performed. Histopathological examination revealed the coexistence of LCH and AXG with prominent emperipolesis characteristic of RDD. Immunohistochemistry showed that most of the large histiocytes were positive for CD68, weakly positive or negative for S100, and negative for CD207 and CD1a, supporting the diagnosis of AXG. The tumor cells with emperipolesis did not show S100‐positive findings characteristic of RDD. The focally aggregated oval histiocytic cells were positive for CD1a, CD207, CD68 and S100, and were compatible with the immunophenotype of LCH cells. In addition, these cells were positive for BRAFV600E mutation. The tumor cells in our patient exhibited a cellular morphology characteristic of multiple histiocytoses in a solitary cutaneous nodule, which may imply an etiological association among LCH, AXG and RDD. To our knowledge, this is the first report of a BRAFV600E mutation‐positive case of LCH coexisting with AXG. Because patients with BRAFV600E mutation have higher risks of multisystemic LCH and recurrence, we should carefully follow up the patient.  相似文献   
87.
88.
89.
90.
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