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   39612篇
  免费   2067篇
  国内免费   141篇
耳鼻咽喉   521篇
儿科学   2557篇
妇产科学   696篇
基础医学   4731篇
口腔科学   1108篇
临床医学   2856篇
内科学   7105篇
皮肤病学   1116篇
神经病学   2343篇
特种医学   1176篇
外科学   5947篇
综合类   1273篇
一般理论   17篇
预防医学   2012篇
眼科学   1424篇
药学   3973篇
  1篇
中国医学   349篇
肿瘤学   2615篇
  2023年   326篇
  2022年   954篇
  2021年   1599篇
  2020年   878篇
  2019年   968篇
  2018年   1371篇
  2017年   1000篇
  2016年   1320篇
  2015年   1323篇
  2014年   1951篇
  2013年   2213篇
  2012年   3104篇
  2011年   3023篇
  2010年   1817篇
  2009年   1427篇
  2008年   2030篇
  2007年   2053篇
  2006年   1872篇
  2005年   1659篇
  2004年   1545篇
  2003年   1311篇
  2002年   1124篇
  2001年   772篇
  2000年   706篇
  1999年   588篇
  1998年   263篇
  1997年   212篇
  1996年   218篇
  1995年   184篇
  1994年   154篇
  1993年   130篇
  1992年   349篇
  1991年   335篇
  1990年   357篇
  1989年   329篇
  1988年   285篇
  1987年   241篇
  1986年   234篇
  1985年   228篇
  1984年   174篇
  1983年   122篇
  1982年   68篇
  1981年   75篇
  1980年   69篇
  1979年   109篇
  1978年   71篇
  1977年   87篇
  1976年   65篇
  1973年   62篇
  1971年   60篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
We report a rare case of a 44-year-old male who underwent a diagnostic coronary angiogram following a non-ST elevation myocardial infarction complicated by an aortic valve leaflet tear requiring surgical intervention. Routine transthoracic echocardiogram demonstrated a mobile echogenic structure prolapsing into the left ventricular outflow tract. An intraoperative transesophageal echocardiogram confirmed that the structure originated from the ventricular side of left coronary cusp, causing malcoaptation between left and right coronary cusps, and subsequent moderate to severe aortic regurgitation.  相似文献   
992.
We present images from computed tomography angiography in a 40-year-old female with a calcified pseudo-aneurysm in her left coronary artery, who had previously undergone repair of tetralogy of Fallot.  相似文献   
993.
We present a case of type B aortic dissection with a rare aortic arch branching variation whereby two separate brachiocephalic trunks arise from the arch. This case also highlights the potential implications of this variant in the management of thoracic aortic dissections and aneurysms.  相似文献   
994.
995.
Cartilage is avascular with limited to no regenerative capacity, so its loss could be a challenge for reconstructive surgery. Current treatment options for damaged cartilage are also limited. In this aspect there is a tremendous need to develop an ideal cartilage-mimicking biomaterial that could repair maxillofacial defects. Considering this fact in this study we have prepared twelve silicone-based materials (using Silicone 40, 60, and 80) reinforced with hydroxyapatite, tri-calcium phosphate, and titanium dioxide which itself has proven their efficacy in several studies and able to complement the shortcomings of using silicones. Among the mechanical properties (Young’s modulus, tensile strength, percent elongation, and hardness), hardness of Silicone-40 showed similarities with goat ear (P > .05). Silicone peaks have been detected in FTIR. Both AFM morphology and SEM images of the samples confirmed more roughed surfaces. All the materials were nonhemolytic in hemocompatibility tests, but among the twelve materials S2, S3, S5, and S6 showed the least hemolysis. For all tested bacterial strains, adherence was lower on each material than that grown on the plain industrial silicone material which was used as a positive control. S2, S3, S5, and S6 samples were selected as the best based on mechanical characterizations, surface characterizations, in vitro hemocompatibility tests and bacterial adherence activity. So, outcomes of this present study would be promising when developing ideal cartilage-mimicking biocomposites and their emerging applications to treat maxillofacial defects due to cartilage damage.  相似文献   
996.
International Urology and Nephrology - Osteopontin (OPN) is evolving as a novel biomarker of injury, overall survival and renal outcome in critically ill patients with acute kidney injury (AKI),...  相似文献   
997.
998.
Our current understanding of emmetropisation and myopia development has evolved from decades of work in various animal models, including chicks, non-human primates, tree shrews, guinea pigs, and mice. Extensive research on optical, biochemical, and environmental mechanisms contributing to refractive error development in animal models has provided insights into eye growth in humans. Importantly, animal models have taught us that eye growth is locally controlled within the eye, and can be influenced by the visual environment. This review will focus on information gained from animal studies regarding the role of optical mechanisms in guiding eye growth, and how these investigations have inspired studies in humans. We will first discuss how researchers came to understand that emmetropisation is guided by visual feedback, and how this can be manipulated by form-deprivation and lens-induced defocus to induce refractive errors in animal models. We will then discuss various aspects of accommodation that have been implicated in refractive error development, including accommodative microfluctuations and accommodative lag. Next, the impact of higher order aberrations and peripheral defocus will be discussed. Lastly, recent evidence suggesting that the spectral and temporal properties of light influence eye growth, and how this might be leveraged to treat myopia in children, will be presented. Taken together, these findings from animal models have significantly advanced our knowledge about the optical mechanisms contributing to eye growth in humans, and will continue to contribute to the development of novel and effective treatment options for slowing myopia progression in children.  相似文献   
999.
1000.
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