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   3444093篇
  免费   281398篇
  国内免费   13332篇
耳鼻咽喉   46865篇
儿科学   109323篇
妇产科学   89466篇
基础医学   548197篇
口腔科学   92937篇
临床医学   314219篇
内科学   607610篇
皮肤病学   91306篇
神经病学   294298篇
特种医学   134149篇
外国民族医学   288篇
外科学   524949篇
综合类   102384篇
现状与发展   24篇
一般理论   2378篇
预防医学   295257篇
眼科学   78100篇
药学   235344篇
  26篇
中国医学   9340篇
肿瘤学   162363篇
  2021年   54928篇
  2020年   35004篇
  2019年   57935篇
  2018年   71234篇
  2017年   54309篇
  2016年   59715篇
  2015年   73861篇
  2014年   108013篇
  2013年   173130篇
  2012年   94250篇
  2011年   94729篇
  2010年   116946篇
  2009年   121250篇
  2008年   81982篇
  2007年   85493篇
  2006年   95312篇
  2005年   91105篇
  2004年   92664篇
  2003年   83401篇
  2002年   73184篇
  2001年   102606篇
  2000年   95243篇
  1999年   95292篇
  1998年   64560篇
  1997年   62606篇
  1996年   60768篇
  1995年   56201篇
  1994年   50451篇
  1993年   47130篇
  1992年   67616篇
  1991年   64878篇
  1990年   61497篇
  1989年   60688篇
  1988年   56505篇
  1987年   55251篇
  1986年   52693篇
  1985年   52281篇
  1984年   48182篇
  1983年   44342篇
  1982年   41730篇
  1981年   39441篇
  1980年   37168篇
  1979年   40696篇
  1978年   36301篇
  1977年   32870篇
  1976年   30137篇
  1975年   29021篇
  1974年   30515篇
  1973年   29622篇
  1972年   27869篇
排序方式: 共有10000条查询结果,搜索用时 9 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.
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   
998.
999.
1000.
OBJECTIVE: To evaluate the effect of statins on aneurysm growth in a group of consecutive patients under surveillance for infrarenal aortic aneurysms (AAA). MATERIALS AND METHODS: All patients (59 statin users, 91 non-users) under surveillance between January 2002 and August 2005 with a follow-up for aneurysm growth of at least 12 months and a minimum of three diameter evaluations were retrospectively included in the analysis. Multiple regression analysis, weighted with the number of observations, was performed to test the influence of statins on AAA growth rate. RESULTS: During a median period of 3.1 (1.1-13.1) years the overall mean aneurysm growth rate was 2.95+/-2.8 mm/year. Statin users had a 1.16 mm/year lower AAA growth rate compared to non-users (95% CI 0.33-1.99 mm/year). Increased age was associated with a slower growth (-0.09 mm/year per year, p = 0.003). Female gender (+1.82 mm/year, p = 0.008) and aneurysm diameter (+0.06 mm/year per mm, p = 0.049) were associated with increased AAA growth. The use of non-steroidal anti-inflammatory drugs, chronic lung disease, or other cardiovascular risk factors were not independently associated with AAA growth. CONCLUSIONS: Statins appear to be associated with attenuation of AAA growth, irrespective of other known factors influencing aneurysm growth.  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