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   233篇
  免费   12篇
儿科学   9篇
妇产科学   6篇
基础医学   29篇
口腔科学   24篇
临床医学   30篇
内科学   67篇
皮肤病学   1篇
神经病学   9篇
特种医学   3篇
外科学   32篇
综合类   2篇
预防医学   7篇
眼科学   2篇
药学   11篇
肿瘤学   13篇
  2022年   3篇
  2021年   6篇
  2020年   2篇
  2019年   2篇
  2018年   4篇
  2017年   2篇
  2016年   6篇
  2015年   4篇
  2014年   4篇
  2013年   7篇
  2012年   19篇
  2011年   12篇
  2010年   8篇
  2009年   8篇
  2008年   14篇
  2007年   12篇
  2006年   7篇
  2005年   13篇
  2004年   12篇
  2003年   12篇
  2002年   13篇
  2001年   2篇
  2000年   4篇
  1999年   3篇
  1998年   3篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1994年   2篇
  1992年   5篇
  1991年   4篇
  1990年   5篇
  1989年   4篇
  1988年   6篇
  1987年   11篇
  1986年   3篇
  1985年   5篇
  1984年   2篇
  1983年   4篇
  1980年   1篇
  1979年   2篇
  1978年   1篇
  1973年   1篇
  1972年   1篇
  1969年   2篇
排序方式: 共有245条查询结果,搜索用时 0 毫秒
241.
A young woman who was experiencing repeated convulsions was admitted. The patient's brain magnetic resonance image revealed reversible posterior leukoencephalopathy. Blood pressure fluctuated at times to more than 200 mmHg, and the measurement of the right and left upper arms differed by approximately 70 mmHg. Enhanced computed tomography revealed stenotic lesions of some arteries including the left renal artery. Such findings led to an initial diagnosis of Takayasu arteritis and hypertensive encephalopathy caused by renovascular hypertension. A percutaneous transluminal renal angioplasty was successfully performed. The patient's blood pressure returned to normal value without the use of antihypertensive drugs.  相似文献   
242.
We report the case of an 18-year-old woman with suprasellar germinoma masquerading as lymphocytic hypophysitis, which was associated with central diabetes insipidus, delayed sexual development, and hypopituitarism. Magnetic resonance imaging revealed an enlarged pituitary gland, thickened pituitary stalk, and a mass lesion in the inferior hypothalamus; these findings are typical of lymphocytic hypophysitis. Despite the administration of prednisolone therapy for 3 months, an enlarged irregular cystic mass lesion developed in the pituitary stalk and inferior hypothalamus. Open cranial surgery of the posterior pituitary revealed the presence of a germinoma. Therefore, chemotherapy and stereotactic radiation therapy were administered, resulting in complete remission of the germinoma. This case illustrates that the presence of an intrasellar mass lesion in association with pituitary stalk thickening can often cause difficulties in differential diagnosis. We believe that lymphocytic hypophysitis in pubertal children may be the first sign of a host reaction to an occult germinoma.  相似文献   
243.
Given the significance of carbohydrates in life, medicine, and industry, the development of simple and efficient de novo methods to synthesize carbohydrates are highly desirable. Organocatalytic asymmetric assembly reactions are powerful tools to rapidly construct molecules with stereochemical complexity from simple precursors. Here, we present a simple and robust methodology for the asymmetric synthesis of pyranose derivatives with talo- and manno- configurations from simple achiral precursors through organocatalytic asymmetric intermolecular Michael–Henry reaction sequences. In this process, (tert-butyldimethylsilyloxy)acetaldehyde 1 was successfully utilized in two ways: as a donor in a highly selective anti-Michael reaction and as an acceptor in a consecutive Henry reaction. Varied nitroolefins served as Michael acceptors and varied aldehydes substituted for 1 as Henry acceptors providing for the construction of a wide range of carbohydrates with up to 5 stereocenters. In these reactions, a catalyst-controlled Michael reaction followed by a substrate-controlled Henry reaction provided 3,4-dideoxytalose derivatives 6 in a highly stereoselective manner. The Henry reaction was affected by addition of a simple base such as triethylamine: A complex chiral base was not necessary. 3,4-Dideoxymannose derivatives 7 were produced by simply changing the base from triethylamine to 1,8-diazabicyclo[5.4.0]undec-7-ene. Extension of this methodology to a syn-Michael initiated sequence was also successful. A mechanistic discussion is provided to explain the unusual substrate-induced stereoselectivity of the Henry reaction.  相似文献   
244.
245.
The mandible is a crucial organ in both clinical and biological fields due to the high frequency of congenital anomalies and the significant morphological changes during evolution. Primary cilia play a critical role in many biological processes, including the determination of left/right axis patterning, the regulation of signaling pathways, and the formation of bone and cartilage. Perturbations in the function of primary cilia are known to cause a wide spectrum of human diseases: the ciliopathies. Craniofacial dysmorphologies, including mandibular deformity, are often seen in patients with ciliopathies. Mandibular development is characterized by chondrogenesis and osteogenesis; however, the role of primary cilia in mandibular development is not fully understood. To address this question, we generated mice with mesenchymal deletions of the ciliary protein, Ift88 (Ift88fl/fl;Wnt1Cre). Ift88fl/fl;Wnt1Cre mice showed ectopic mandibular bone formation, whereas Ift88 mutant mandible was slightly shortened. Meckel's cartilage was modestly expanded in Ift88fl/fl;Wnt1Cre mice. The downregulation of Hh signaling was found in most of the mesenchyme of Ift88 mutant mandible. However, mice with a mesenchymal deletion of an essential molecule for Hh signaling activity, Smo (Smofl/fl;Wnt1Cre), showed only ectopic mandibular formation, whereas Smo mutant mandible was significantly shortened. Ift88 is thus involved in chondrogenesis and osteogenesis during mandibular development, partially through regulating Sonic hedgehog (Shh) signaling.  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