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   2634652篇
  免费   210188篇
  国内免费   4904篇
耳鼻咽喉   35862篇
儿科学   87631篇
妇产科学   74901篇
基础医学   374224篇
口腔科学   75586篇
临床医学   236390篇
内科学   515634篇
皮肤病学   58612篇
神经病学   216169篇
特种医学   103157篇
外国民族医学   897篇
外科学   395543篇
综合类   64778篇
现状与发展   6篇
一般理论   970篇
预防医学   207264篇
眼科学   60941篇
药学   192600篇
  3篇
中国医学   5478篇
肿瘤学   143098篇
  2018年   27448篇
  2017年   21088篇
  2016年   23778篇
  2015年   27037篇
  2014年   37945篇
  2013年   57317篇
  2012年   77464篇
  2011年   81856篇
  2010年   48338篇
  2009年   46197篇
  2008年   76993篇
  2007年   81429篇
  2006年   82664篇
  2005年   80222篇
  2004年   77776篇
  2003年   74388篇
  2002年   72302篇
  2001年   125893篇
  2000年   129511篇
  1999年   108842篇
  1998年   30514篇
  1997年   27622篇
  1996年   27563篇
  1995年   26503篇
  1994年   24511篇
  1993年   23160篇
  1992年   86266篇
  1991年   83159篇
  1990年   80628篇
  1989年   77494篇
  1988年   71816篇
  1987年   70486篇
  1986年   66637篇
  1985年   63900篇
  1984年   48292篇
  1983年   41325篇
  1982年   24725篇
  1981年   22043篇
  1979年   44742篇
  1978年   31268篇
  1977年   26311篇
  1976年   24782篇
  1975年   25743篇
  1974年   31469篇
  1973年   30384篇
  1972年   28064篇
  1971年   26129篇
  1970年   24422篇
  1969年   22754篇
  1968年   21050篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
92.
The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child.  相似文献   
93.
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   
94.
95.
Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.  相似文献   
96.
97.
98.
99.
Zusammenfassung Viele gastrointestinale Tumoren werden im Rahmen multimodaler Therapiekonzepte behandelt. Für den Chirurgen ist die neoadjuvante, präoperative Behandlung von besonderem Interesse, da sie durch therapiebedingte Nebenwirkungen und Komplikationen zu einer Beeinflussung des postoperativen Verlaufs führen kann. Die neoadjuvante Radiochemotherapie ist fester Bestandteil der Therapie beim primären T4-Rektumkarzinom, beim Rektumkarzinomrezidiv und bei tief sitzenden primären Rektumkarzinomen. Durch Erhöhung der R0-Resektionsrate können die lokale Tumorkontrolle verbessert und die Überlebenszeit verlängert werden. Die postoperative Komplikationsrate ist dabei nicht wesentlich erhöht. In der Behandlung des primär resektablen Ösophaguskarzinoms deutet sich ein Vorteil der neoadjuvanten Radiochemotherapie im Vergleich zur alleinigen Chirurgie an. Beim lokal fortgeschrittenen Ösophaguskarzinom bietet die präoperative Radiochemotherapie häufig die einzige Chance zur Resektion, jedoch mit einer deutlich erhöhten postoperativen Morbidität und Mortalität. Die Wirksamkeit und Sicherheit einer neoadjuvanten Chemo- oder kombinierten Radiochemotherapie beim fortgeschrittenen Magenkarzinom wird derzeit im Rahmen von Studienprotokollen untersucht.  相似文献   
100.
Using complete denture treatment as an introduction to clinical patient care for dental students, the purposes of the Complete Denture Prosthodontics Transition Clinic at the University of Colorado School of Dentistry are to reduce the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience, and to encourage development of student self-confidence and skills. In the 2002 spring semester, faculty at the University of Colorado School of Dentistry initiated the Complete Denture Prosthodontics Transition Clinic for DS-II (second-year) dental students, as an introduction to clinical patient care. Each patient was assigned to a team of two dental students. Three Division of Prosthodontics faculty members staffed each clinic session, providing a student-to-faculty ratio of approximately 6.6:1 and a patient-to-faculty ratio of approximately 3.3:1. All DS-II students in the Class of 2004 delivered their first complete dentures no later than 8 months (average, 184 days) after the last day of the preclinical complete denture prosthodontics course. The time from the diagnostic appointment through the denture placement appointment averaged 39 days for patients treated in this program, compared with an average of 98 days or more for previous classes. The program was successful in achieving the goal of reducing the time lapse between the preclinical complete denture prosthodontics course and the first denture patient experience.  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