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   279991篇
  免费   16388篇
  国内免费   1352篇
耳鼻咽喉   4085篇
儿科学   8310篇
妇产科学   7827篇
基础医学   40495篇
口腔科学   6215篇
临床医学   23795篇
内科学   53273篇
皮肤病学   7762篇
神经病学   21256篇
特种医学   13210篇
外国民族医学   32篇
外科学   41230篇
综合类   3762篇
现状与发展   5篇
一般理论   110篇
预防医学   15663篇
眼科学   7766篇
药学   21861篇
中国医学   1915篇
肿瘤学   19159篇
  2022年   2995篇
  2021年   5383篇
  2020年   2881篇
  2019年   4237篇
  2018年   5314篇
  2017年   4035篇
  2016年   5317篇
  2015年   6882篇
  2014年   8544篇
  2013年   10780篇
  2012年   15801篇
  2011年   15505篇
  2010年   9279篇
  2009年   8070篇
  2008年   12605篇
  2007年   12724篇
  2006年   12125篇
  2005年   11812篇
  2004年   10922篇
  2003年   9829篇
  2002年   8966篇
  2001年   11421篇
  2000年   11073篇
  1999年   9182篇
  1998年   2970篇
  1997年   2593篇
  1996年   2322篇
  1995年   2098篇
  1994年   1864篇
  1993年   1791篇
  1992年   5415篇
  1991年   5214篇
  1990年   4973篇
  1989年   4649篇
  1988年   4179篇
  1987年   3960篇
  1986年   3855篇
  1985年   3555篇
  1984年   2618篇
  1983年   2209篇
  1982年   1347篇
  1981年   1318篇
  1979年   2379篇
  1978年   1779篇
  1977年   1526篇
  1976年   1295篇
  1975年   1501篇
  1974年   1588篇
  1973年   1551篇
  1972年   1375篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Critical size defect in the canine mandible.   总被引:3,自引:0,他引:3  
OBJECTIVE: The purpose of this study was to determine the minimum size defect in a canine mandible that would not spontaneously heal during the dog's natural life (the critical size defect). STUDY DESIGN: Sixteen adult female mongrel dogs underwent continuity resection on both sides of the mandible to create bilateral defects. In 8 dogs, mandibular defects ranging from 5 to 20 mm were created with periosteal resection. In the other 8 dogs, mandibular defects ranging from 30 to 60 mm were created preserving the periosteum. The dogs were then killed at 6 months and the defects examined using radiographs and histologic analysis. RESULTS: When the periosteum was removed, mandibular defects greater than 15 mm failed to heal across the entire defect. However, when the periosteum was preserved, mandibular defects needed to be greater than 50 mm in order to fail to heal. CONCLUSION: The critical size defect in a canine mandible model is 15 mm when the periosteum is removed and 50 mm when the periosteum is preserved.  相似文献   
72.
Occupational diseases Nos. 2108 and 2110 correspond to intervertebral disc-related diseases of the lumbar spine from many years of carrying or lifting heavy loads, occupations in extreme postures of full flexion or oscillation of the whole body when seated, and which compel the cessation of all activities which are or could be the cause for the origin, exacerbation or recurrence of the disease. These occupational diseases came into force at the start of 1993, but there have been considerable problems in their implementation. The present Part I of the contribution is the result of the work of an interdisciplinary study group and contains medical criteria for the assessment of possibly strain-related clinical characteristics and the evaluation of other possible causes. Part II is to be published in Volume 4/2005 and will deal with questions related to forced cessation and to the assessment of the loss of earning ability. Agreement was reached in many areas related to the assessment of occupational claims. This should allow for evidence-based decision making in the future for the occupational diseases Nos. 2108 and 2110.  相似文献   
73.
74.
OBJECTIVE: This article 1) provides an overview of formal Health Sciences Teaching Scholars Programs as presented in medical education literature and 2) presents information about an innovative multidiscipline Teaching Scholars Program. METHOD: Health Sciences Teaching Scholars Programs and similar programs were reviewed in the medical education literature to identify similar and dissimilar characteristics. The WVU Teaching Scholars Program highlighted in this article is presented with a discussion of goals, objectives, target audiences, course length, session frequency, program topics, learning methods, and assessments of the programs. A summary of the WVU Teaching Scholars Program and two Teaching Scholars Programs at McGill University and the University of Toronto were presented at the Association for American Medical Colleges (AAMC) annual meeting in 2006 for input from the general medical education audience. RESULTS: Comparisons of Health Sciences Teaching Scholars Programs reveal that successful programs are uniquely shaped by their educational environments. Scholars report that they value learning new teaching methods and improving their educational careers. CONCLUSION: Teaching Scholars Programs are valuable for the development of enhancing both teaching and scholarship in Health Sciences Programs and must adapt to the uniqueness of their respective educational environments and must continue to nurture scholars beyond graduation.  相似文献   
75.
76.
77.
We investigate the controlled release of lidocaine hydrochloride from the doped silica-based xerogels. In the xerogel preparation, tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), and propyltriethoxysilane (PTES) are used as precursors, and a nonionic surfactant Igepal CO 720 is used as a dopant. The experimental results suggest that the release of lidocaine hydrochloride can be easily controlled by partially substituting TEOS with the organosilanes, and/or by adding the dopant. Adding the organosilane precursors lowers the release of both the drug and the surfactant in the order of TEOS, MTES/TEOS, and PTES/TEOS xerogels. The release from the PTES/TEOS xerogels is much lower than that from the other xerogels. The release of lidocaine hydrochloride is obviously suppressed by the addition of Igepal CO 720, while the release of Igepal CO 720 is slightly promoted by the addition of the drug. The overall release process is found to be diffusion-controlled, and the release behaviors can be well explained by considering the effects of the textual properties of the xerogels and the interactions among the drug, the surfactant, and the xerogel matrices.  相似文献   
78.
79.
The information contained in package inserts varies from country to country in Europe, although other regulatory aspects of data presentation are quite similar. West Germany's Drug Law of 1976 requires 11 items to be included in the package insert for both patient and health professional: name/address of manufacturer; drug name; active constituents; indications; contraindications; side effects; drug interactions; dosage instructions; method and duration of application; statement that drug should not be used after expiration date; and statement that drug should be kept out of reach of children. All information must be submitted to the Health Office at the time of application or the applicant is liable for criminal prosecution. Documentation of side effects must be complete, although no special form is required. Similarly, causality assessment needs to be made even though specific algorithms are not required. Proposed amendments to the Drug Law will include additional information to physicians concerning the overdose instructions, pharmacological properties, and bioavailability of the drug. Registration procedures are the same throughout Europe and are called Summary of Products Characteristics. Assessment reports are also required for each new chemical entity in the European Community.  相似文献   
80.
Behavioral state-specific changes in human hippocampal theta activity   总被引:1,自引:0,他引:1  
Although there has been extensive examination of the behavioral and physiologic correlates of hippocampal theta activity in animals, the human literature consists of a single case study. We investigated the differential effects of four behavioral states on human hippocampal theta activity in 16 epilepsy surgery patients. Behavioral conditions included resting eyes closed (RC), resting eyes open (RO), eyes open with auditory word activation (AW), and eyes open with visuospatial activation (VS). Hippocampal theta activity decreased during both RO and VS compared to both RC and AW. There were reciprocal changes in delta activity. Comparisons of RO to VS and of RC to AW were nonsignificant. The results demonstrate state-specific changes in human hippocampal theta and are consistent with the animal literature that relates hippocampal theta to sensorimotor integration and forebrain volitional mechanisms.  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