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   3106篇
  免费   236篇
  国内免费   21篇
耳鼻咽喉   8篇
儿科学   159篇
妇产科学   28篇
基础医学   474篇
口腔科学   91篇
临床医学   449篇
内科学   549篇
皮肤病学   57篇
神经病学   229篇
特种医学   290篇
外科学   317篇
综合类   49篇
一般理论   2篇
预防医学   282篇
眼科学   73篇
药学   116篇
  1篇
中国医学   1篇
肿瘤学   188篇
  2021年   33篇
  2020年   24篇
  2019年   38篇
  2018年   44篇
  2017年   33篇
  2016年   34篇
  2015年   56篇
  2014年   66篇
  2013年   114篇
  2012年   106篇
  2011年   96篇
  2010年   99篇
  2009年   92篇
  2008年   95篇
  2007年   104篇
  2006年   107篇
  2005年   99篇
  2004年   96篇
  2003年   97篇
  2002年   84篇
  2001年   62篇
  2000年   61篇
  1999年   78篇
  1998年   106篇
  1997年   92篇
  1996年   76篇
  1995年   70篇
  1994年   50篇
  1993年   58篇
  1992年   51篇
  1991年   77篇
  1990年   70篇
  1989年   97篇
  1988年   96篇
  1987年   80篇
  1986年   64篇
  1985年   60篇
  1984年   41篇
  1983年   35篇
  1982年   29篇
  1981年   37篇
  1980年   27篇
  1979年   33篇
  1978年   40篇
  1977年   23篇
  1976年   28篇
  1975年   26篇
  1973年   22篇
  1972年   25篇
  1969年   25篇
排序方式: 共有3363条查询结果,搜索用时 0 毫秒
21.
A lump on the midface of a child can pose as a diagnostic dilemma. There is a wide variety of possible differential diagnoses, ranging from simple benign conditions such as a sebaceous cyst, dermoid cyst, lipoma, neuroma and neurofibroma, to potentially devastating conditions such as odontogenic myxoma.A case of a child in which the formulation of a definite diagnosis was clinically and histologically challenging is presented.  相似文献   
22.
23.
This article is an overview of the promotion function as a part of the ATM's marketing mix. It approaches various promotion decision areas from a managerial perspective, focusing upon some key components of promotion planning. Rather than provide specific operational or implementation details (how to write a brochure) it is more conceptual in nature and offers a framework for promotion planners. The article addresses promotion management, promotion objectives, analysis for promotion planning, the promotion mix, and addresses the benefits and limitations of some specific promotion tools available to the ATM manager. It treats ATMs as a service and reveals specific implications for promotion strategy dictated by services. The article also reports promotion tools employed by Alabama ATMs citing data from the Alabama study.  相似文献   
24.
25.
26.
BACKGROUND: Acquired cerebriform intradermal naevus (CIN) is a rare form of pseudo cutis verticis gyrata. CASE REPORT: A case of acquired CIN of the scalp in a 46-year-old male patient is presented. The clinical and histopathological presentations of CIN are described and the therapeutic possibilities are discussed. CONCLUSIONS: In each individual case the physician must decide whether to do surgery or follow a wait-and-see policy. There is little risk of malignant change of CIN, and surgical excision of such lesions often involves evident mutilation.  相似文献   
27.
Objective: Right upper lobe collapse is a common radiographic finding in intubated children. We hypothesized that deep suctioning and uncontrolled negative pressures during endotracheal tube suctioning were significant contributory factors. Methods : The incidence of right upper lobe (RUL) collapse in intubated, ventilated children on a paediatric cardiac intensive care unit was determined over a 3-month period ( n = 102). Graduated suction catheters and suction vacuums of < 165 cm H2O were then introduced. Another prospective audit was carried out 3 months later ( n = 60). Results : We found that 24% developed RUL collapse and 4 developed an apical pneumothorax. Following the introduction of graduated catheters and controlled vacuums pressures, a significant reduction in the incidence of RUL collapse, to 7%, was observed ( p < 0.05). Conclusions : We conclude that high negative pressure and deep-suctioning causes RUL collapse in children. Any lobar collapse not only prolongs the child's stay in intensive care, but can be associated with further morbidity which may have a serious implication. By improving suctioning technique this morbidity can be significantly reduced.  相似文献   
28.
Edentulous ridge augmentation has evolved from an attempt to control progressive atrophy of both denture-bearing bone and soft tissue. Preprosthetic surgery to reverse these undesirable conditions should only be attempted after other methods, such as proper denture construction, proper patient compliance, and patient management have been unsuccessful. Also a thorough evaluation by both a prosthodontist and an oral surgeon is required. Prosthodontically, the surgical procedure should produce the following features: (1) enlargement of the area of bony support, (2) improved contour of the ridge for denture stability, and (3) elimination of the displacing action of muscle attachments on the complete denture. Ideally we would like to combine all of these distinct features to arrive at the goal of optimum denture retention. The oral surgeon must also be aware of these principles, and in essence, determines the immediate post-surgical results. However, the oral surgeon is also limited by specific patient factors such as systemic conditions, oral health maintanence, and finances. He must recognize these and determine which surgical methods would give the best denture retention and patient service. It is in this context that the prosthodontist and oral surgeon must work together to facilitate total patient care.  相似文献   
29.
Recombination of deltaRec to psiJalpha will delete the TCR delta gene, which is thought to play an important role in the bifurcation of the TCR alphabeta versus TCR gammadelta differentiation lineages. We recently detected a DNA-binding protein in human thymocytes, the so- called PJA-BP, which recognizes the psiJalpha gene segment and might be one of the factors involved in the regulation of preferential deltaRec- psiJalpha rearrangements. We now investigate PJA-BP expression and its correlation with TCR delta gene deletion in thymocytes. Our electrophoretic mobility shift assay experiments showed that the PJA-BP is evolutionary conserved in human, murine and simian thymocytes. Using a large series of human hematopoietic malignancies (n = 30), we conclude that PJA-BP expression is thymocyte specific and seems to be restricted to thymocytes committed to the TCR alphabeta lineage. Analysis of seven well-defined human thymocyte subpopulations showed that preferential deltaRec-psiJalpha rearrangements as well as PJA-BP expression can be detected from the immature CD34-/CD1+/CD3- /CD4+/CD8alpha+beta- thymocyte differentiation stage onwards. These experiments indicate that expression of PJA-BP in human thymocytes starts simultaneously with preferential deltaRec-psiJalpha rearrangements, which supports our hypothesis that PJA-BP is one of the factors involved in the preferential recombination of deltaRec to psiJalpha.   相似文献   
30.
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