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   721篇
  免费   55篇
  国内免费   15篇
耳鼻咽喉   5篇
儿科学   47篇
妇产科学   11篇
基础医学   90篇
口腔科学   31篇
临床医学   84篇
内科学   163篇
皮肤病学   34篇
神经病学   19篇
特种医学   130篇
外科学   61篇
综合类   37篇
预防医学   23篇
眼科学   5篇
药学   33篇
中国医学   2篇
肿瘤学   16篇
  2023年   4篇
  2022年   2篇
  2021年   12篇
  2020年   12篇
  2019年   17篇
  2018年   11篇
  2017年   17篇
  2016年   17篇
  2015年   23篇
  2014年   25篇
  2013年   32篇
  2012年   14篇
  2011年   10篇
  2010年   46篇
  2009年   35篇
  2008年   15篇
  2007年   23篇
  2006年   13篇
  2005年   13篇
  2004年   8篇
  2003年   11篇
  2002年   8篇
  2001年   6篇
  2000年   11篇
  1999年   10篇
  1998年   44篇
  1997年   38篇
  1996年   37篇
  1995年   23篇
  1994年   33篇
  1993年   30篇
  1992年   11篇
  1991年   8篇
  1990年   8篇
  1989年   21篇
  1988年   16篇
  1987年   15篇
  1986年   10篇
  1985年   8篇
  1984年   5篇
  1983年   10篇
  1982年   13篇
  1981年   9篇
  1980年   14篇
  1978年   4篇
  1977年   13篇
  1976年   7篇
  1975年   5篇
  1956年   3篇
  1955年   2篇
排序方式: 共有791条查询结果,搜索用时 0 毫秒
41.
OBJECTIVE: To evaluate the relation between apathy and development of dementia in patients with amnestic mild cognitive impairment (MCI). METHODS: Two hundred and fifty-one French-speaking outpatients fulfilling the criteria of amnestic MCI were enrolled. Apathy was assessed with the Apathy Inventory (IA). Neuropsychiatric evaluation also included the Goldberg anxiety scale and the Montgomery and Asberg Depressive Rating Scale (MADRS). The main end point considered after a 1-year follow-up was the development of dementia of Alzheimer type (DAT). RESULTS: At baseline there were 86 (39.8%) subjects presenting at least one symptom of apathy among the 216 included in analysis. After a 1-year follow-up, 22 patients developed DAT. Of the patients with apathy at baseline 13 (15.1%) developed DAT in comparison with 9 (6.9%) of the non-apathetic patients. At the 1-year follow-up, patients developing DAT had a significantly higher frequency of apathetic symptoms (91.7%) than patients without DAT (26.9%). CONCLUSION: Taking into account that apathy is one of the most frequently observed neuropsychiatric symptoms in MCI and in DAT the present study suggests that patients with MCI and apathy should be more closely observed.  相似文献   
42.
Vroman  L; Adams  AL; Fischer  GC; Munoz  PC 《Blood》1980,55(1):156-159
Using ellipsometry, anodized tantalum interference color, and Coomassie blue staining in conjunction with immunologic identification of proteins adsorbed at interfaces, we have previously found that fibrinogen is the main constituent deposited by plasma onto many man- made surfaces. However, the fibrinogen deposited from normal plasma onto glass and similar wettable materials is rapidly modified during contact activation until it can no longer be identified antigenically. In earlier publications, we have called this modification of the fibrinogen layer "conversion," to indicate a process of unknown nature. Conversion of adsorbed fibrinogen by the plasma was not accompanied by marked change in film thickness, so that we presumed that this fibrinogen was not covered but replaced by other protein. Conversion is now showen to be markedly delayed in plasma lacking high molecular weight kininogen, slightly delayed in plasma lacking factor XII, and normal in plasma that lack factor XI or prekallikrein. We conclude that intact plasma will quickly replace the fibrinogen it has deposited on glass-like surfaces by high molecular weight kininogen and, to a smaller extent, by factor XII. Platelets adhere preferentially to fibrinogen-coated surfaces; human platelets adhere to hydrophobic nonactivating surfaces, since on these, adsorbed firbinogen is not exchanged by the plasma. The adsorbed fibrinogen will be replaced on glass-like surfaces during surface activation of clotting, and platelets failing to find fibrinogen will not adhere.  相似文献   
43.
44.
45.
46.
47.
The extent of length polymorphisms of the heterochromatic and euchromatic segment of the human Y chromosome were investigated in 15 boys with acute leukemia and were compared with 15 normal controls. A greater value of the Yh/F index in relation to controls was established (P < 0.05). The length of the euchromatic segment was also shorter in the patients than the controls (P < 0.05).  相似文献   
48.
ABSTRACT. Serial plasma glucose estimations were performed in 44 light-for-date infants and 17 infants of diabetic mothers fed 2, 3 or 4-hourly with feeds containing 10 % additional carbohydrate in the form of a glucose polymer (Caloreen). In the infants fed 2 and 3-hourly, plasma glucose was higher following the high carbohydrate feeds, particularly immediately before the next feed was due. Given 4-hourly, the high carbohydrate feed had little effect in most light-for-date infants, and in one light-for-date infant and two infants of diabetic mothers the plasma glucose was lower at the end of 4 hours than following normal formula. It is concluded that the addition of glucose polymer to feeds given 2 and 3 hourly has a potentially useful effect in neonates at risk of developing hypoglycaemia, but it cannot be used to increase the feed interval to 4 hours.  相似文献   
49.
A series of 73 hypopharyngeal (Zenker's) diverticula is reported and the choice of treatment and technique of excision are discussed. The problems of excision include operation on an infected site with limited access but few patients are unfit for the procedure. Preoperatively the sac should be packed and the oesophagus stented. The side of approach is unimportant as the condition is essentially midline. Cricopharyngeal myotomy appears to reduce the recurrence rate, possibly by improving coordination of pharyngeal contraction and upper oesophageal relaxation. The use of electrocoagulation is not recommended as 20% of patients require repeated general anaesthesia and the procedure fails in 13%. For all but the smallest pouches, excision is the treatment of choice.  相似文献   
50.
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