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   2348809篇
  免费   181064篇
  国内免费   7741篇
耳鼻咽喉   31880篇
儿科学   77389篇
妇产科学   66424篇
基础医学   331740篇
口腔科学   65880篇
临床医学   207067篇
内科学   468581篇
皮肤病学   53471篇
神经病学   188931篇
特种医学   94313篇
外国民族医学   617篇
外科学   364923篇
综合类   52503篇
现状与发展   3篇
一般理论   683篇
预防医学   182768篇
眼科学   52421篇
药学   171544篇
  6篇
中国医学   4258篇
肿瘤学   122212篇
  2018年   22795篇
  2016年   20730篇
  2015年   23424篇
  2014年   32636篇
  2013年   49369篇
  2012年   63377篇
  2011年   67930篇
  2010年   41613篇
  2009年   40053篇
  2008年   64495篇
  2007年   69462篇
  2006年   70883篇
  2005年   69070篇
  2004年   66287篇
  2003年   64492篇
  2002年   62280篇
  2001年   108035篇
  2000年   111230篇
  1999年   93720篇
  1998年   27845篇
  1997年   24994篇
  1996年   25842篇
  1995年   25335篇
  1994年   23896篇
  1993年   22253篇
  1992年   77398篇
  1991年   75839篇
  1990年   73858篇
  1989年   70818篇
  1988年   66024篇
  1987年   64725篇
  1986年   61568篇
  1985年   59066篇
  1984年   44716篇
  1983年   38236篇
  1982年   23570篇
  1981年   21056篇
  1980年   19749篇
  1979年   41445篇
  1978年   29674篇
  1977年   25291篇
  1976年   23550篇
  1975年   25318篇
  1974年   29825篇
  1973年   28607篇
  1972年   26814篇
  1971年   24846篇
  1970年   22903篇
  1969年   21848篇
  1968年   20526篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
102.
Four clinical trials of porcine islet transplantation have been reported, and there are verbal reports that clinical trials on much larger scales are continuing in centers in China and Russia. The four reported trials are briefly reviewed and, in the light of the present status of experimental islet xenotransplantation, consideration is given to whether such trials are currently justified. The Ethics Committee of the International Xenotransplantation Association has (1) emphasized the need for encouraging studies in non-human primates before clinical trials should be undertaken, (2) mandatory monitoring for the transfer of porcine microorganisms, and (3) careful regulation and oversight by recognized bodies. Other aspects of the topic, such as the need for informed consent, are briefly discussed. We conclude that, at the present time, more data documenting convincing efficacy, focused on clinically applicable immunosuppressive regimens, are needed to justify the initiation of closely monitored clinical trials. A clinical trial may then be justified even though the potential risk to the patients, and possibly for society, will not be zero.  相似文献   
103.
Summary: The mosaic (Atp7a mo-ms ) is an X-linked, lethal mutation in mice. In mosaic mutant males, many clinical features characteristic of defective copper metabolism have been observed and they die at the age of 15 days, exhibiting strongsimilarities to the brindled and macular mutants. About 4% of the mutant males live to sexual maturity and some of them are fertile. In this paper, alterationsin the structure of the kidney from adult mutants are described. Owing to an inherited defect of efflux, copper is accumulated in the kidney of the mutants up to a toxic level and this leads to severe damage of the renal cortex. Pathological changes in the kidney mostly affected the structure of the renal corpuscle and renaltubules.  相似文献   
104.
105.
106.
107.
108.
OBJECTIVE: A safe entry zone to tegmental lesions was identified based on intraoperative electrophysiological findings, the compound muscle action potentials (CMAP) from the extraocular muscles, and anatomic considerations. This entry zone is bordered caudally by the intramesencephalic path of the trochlear, laterally by the spinothalamic tract, and rostrally by the caudal margin of the brachium of the superior colliculus. METHODS: Four intrinsic midbrain lesions were operated upon via the safe entry zone using the infratentorial paramedian supracerebellar approach. All lesions involved the tegmentum and included an anaplastic astrocytoma, a metastatic brain tumor, a radiation necrosis, and a cavernous angioma. CMAP were bilaterally monitored from the inferior recti (for oculomotor function) and superior oblique (for trochlear nerve function) muscles. RESULTS: In three of four cases, CMAP related to the oculomotor nerve were obtained upon stimulation at the cavity wall after removal of the tumor. Stimulation at the surface of the quadrigeminal plate, however, did not cause any CMAP response. Using this monitoring as an indicator, the lesions were totally removed. CONCLUSIONS: In the surgery of tegmental lesions, CMAP monitoring from extraocular muscles is particularly helpful to prevent damage to crucial neural structures during removal of intrinsic lesions, but less so to select the site of the medullary incision. The approach via the lateral part of the colliculi is considered to be a safe route to approach the tegmental lesions.  相似文献   
109.
This article describes the proceedings of the 2006 Annual Meeting of the Fetal Alcohol Spectrum Disorders Study Group (FASDSG), which was held in Baltimore, Maryland on June 24, 2006. The meeting was held in conjunction with the annual meeting of the Research Society on Alcoholism and was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism. The 2005-2006 FASDSG officers, Daniel J. Bonthius (President), Heather Carmichael Olson (Vice-President), and Jennifer Thomas (Secretary-Treasurer), organized the meeting. Nationally prominent speakers delivered plenary lectures on topics of newborn screening, ethics, and neuroscience. Selected members of the FASDSG provided brief scientific data (FASt) reports, describing new research findings. Representatives from national agencies involved in fetal alcohol syndrome (FAS) research, treatment, and prevention provided updates regarding priorities, funding, and agency activities. Presentations were also made by the 2006 Student Merit Award recipient and by the 2006 Rosett Award recipient. The meeting served as a forum for clinicians, neuroscientists, psychologists, social scientists, and other professionals to discuss recent advances in FAS research and to identify the most important gaps in the understanding of alcohol-induced teratology.  相似文献   
110.
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