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   5371176篇
  免费   399005篇
  国内免费   16537篇
耳鼻咽喉   76083篇
儿科学   171144篇
妇产科学   144390篇
基础医学   792795篇
口腔科学   155607篇
临床医学   494357篇
内科学   977940篇
皮肤病学   126123篇
神经病学   445253篇
特种医学   207653篇
外国民族医学   1135篇
外科学   797588篇
综合类   149764篇
现状与发展   25篇
一般理论   3092篇
预防医学   454351篇
眼科学   126682篇
药学   382877篇
  28篇
中国医学   14125篇
肿瘤学   265706篇
  2021年   58944篇
  2019年   61079篇
  2018年   78900篇
  2017年   60458篇
  2016年   66920篇
  2015年   79434篇
  2014年   114668篇
  2013年   180822篇
  2012年   157178篇
  2011年   167723篇
  2010年   136703篇
  2009年   135169篇
  2008年   151320篇
  2007年   163274篇
  2006年   168984篇
  2005年   162871篇
  2004年   162621篇
  2003年   152002篇
  2002年   140173篇
  2001年   206635篇
  2000年   203586篇
  1999年   182328篇
  1998年   77208篇
  1997年   71525篇
  1996年   69612篇
  1995年   64864篇
  1994年   59051篇
  1993年   54719篇
  1992年   136597篇
  1991年   131762篇
  1990年   127414篇
  1989年   123874篇
  1988年   114779篇
  1987年   112644篇
  1986年   106723篇
  1985年   103533篇
  1984年   83508篇
  1983年   73527篇
  1982年   53757篇
  1981年   49626篇
  1980年   46641篇
  1979年   75299篇
  1978年   58325篇
  1977年   50974篇
  1976年   47193篇
  1975年   48934篇
  1974年   55766篇
  1973年   53855篇
  1972年   50984篇
  1971年   47178篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
背景:针对糖尿病患者Lp(a)水平和冠状动脉疾病(CAD)严重程度之间关系的研究较少并且结论有争议。另外,目前尚无关于apo(a)多态性与上述疾病关系的研究。本研究旨在探讨大样本2型糖尿病患者中冠状动脉粥样硬化的程度与Lp(a)水平及apo(a)多态性的相关性。方法:连续选取227例2型糖  相似文献   
993.
BACKGROUND: The recurrent chronic orofacial swelling caused by orofacial granulomatosis (OFG) can cause significant cosmetic and functional problems but can be prevented if the disease is diagnosed early and promptly treated. Although the enlargement of the lips is described to be the most common presenting complaint, the clinical onset of OFG may be characterized by minor associated mucosal and neurological manifestations, making early diagnosis very difficult or, sometimes, merely presumable. PATIENTS AND METHODS: We retrospectively analyzed the clinical manifestations of 19 patients with OFG, who were examined at our institution between 1998 and 2002, in order to determine their initial manifestations and presenting symptoms. RESULTS: A total of 10 patients showed classical recurrent enlargement of the lips (six lower; four upper) as presenting symptom. In the other nine patients, OFG onset was characterized by transient unilateral facial nerve palsy (two cases), intraoral manifestations (two cases), recurrent swelling of the periorbital area (two cases), of the chin (one case), of the zygomatic area (one case), and of the cheeks (one case). CONCLUSION: Our data underlined that OFG onset could be frequently characterized by widely variable, multiform, and temporary clinical findings. Involvement of atypical sites of the orofacial region and presence of single minor manifestations may occur as presenting symptoms, often preceding the development of traditional clinical findings.  相似文献   
994.
Summary The third-stage larvae of Daniconema anguillae Moravec et K?ie, 1987 are found in the eels fins caught from Dringis Lake (Lithuanian National park). The morphology of these larvae is briefly described.  相似文献   
995.
996.
Stability of transverse expansion in the mandibular arch.   总被引:1,自引:0,他引:1  
This was a retrospective, longitudinal cephalometric and cast study of 29 white patients at pretreatment, posttreatment, and an average of 6 years 3 months postretention. The goal was to assess changes with treatment and retention with the expanding mandibular lingual arch appliance in conjunction with fixed edgewise treatment. Seven mandibular cast measurements were assessed, including arch crowding, arch perimeter, arch length, and arch width at the permanent canines, first premolars, second premolars, and first molars. Cephalometric radiographs were digitized, and 16 cephalometric measurements were made. Repeated-measures analysis of variance and 2-sample t tests were used to determine statistically significant changes. It was found that the expanding lingual arch used for less than 6 months with the mandibular fixed edgewise appliance caused an increase in both the transverse and sagittal dimensions of the mandibular dental arch. Transverse expansion was more stable in the posterior region of the mandibular dental arch than in the anterior region. Mandibular intercanine width increase could be maintained only by fixed retention. Although the maxillary and mandibular incisors were advanced and proclined, lip protrusion did not occur.  相似文献   
997.
998.
Objective: The study explored the semantic content and origins of negative self-beliefs, and their functional links to “not eating enough” and other behaviors, in participants with anorexia nervosa (AN). Method: Fifteen women meeting DSM-IV criteria for AN were compared with 17 dieting and 18 non-dieting women matched on age and number of years of education. The main outcome measure was a semi-structured interview. Results: Six themes were identified in the beliefs of participants with AN. These were, in order of decreasing frequency, powerlessness (present in all but three AN participants), failure, defectiveness, unattractiveness, worthlessness and emptiness. Importantly, powerlessness and failure beliefs were consistently present independent of Beck Depression Inventory-II scores. The negative early life experiences associated with these beliefs had high distress and responsibility ratings. Participants with AN reported that they employed specific behaviors, particularly ‘not eating enough,’ and ‘placating others,’ to try to reduce the cognitive and emotional impact of their negative self-beliefs. Discussion: The findings are discussed in relation to the role of powerlessness and the function of “not eating enough” in cognitive theory and therapy for AN.
  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