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   2051399篇
  免费   158702篇
  国内免费   7653篇
耳鼻咽喉   27314篇
儿科学   66258篇
妇产科学   57006篇
基础医学   284712篇
口腔科学   56489篇
临床医学   180577篇
内科学   416710篇
皮肤病学   46886篇
神经病学   166987篇
特种医学   83753篇
外国民族医学   596篇
外科学   321557篇
综合类   46993篇
现状与发展   2篇
一般理论   636篇
预防医学   159541篇
眼科学   44903篇
药学   145357篇
  5篇
中国医学   3723篇
肿瘤学   107749篇
  2018年   20474篇
  2016年   18551篇
  2015年   20975篇
  2014年   29628篇
  2013年   44896篇
  2012年   56855篇
  2011年   60806篇
  2010年   37683篇
  2009年   36426篇
  2008年   57376篇
  2007年   61300篇
  2006年   62320篇
  2005年   60744篇
  2004年   57973篇
  2003年   56422篇
  2002年   54283篇
  2001年   96557篇
  2000年   99479篇
  1999年   83661篇
  1998年   24516篇
  1997年   22108篇
  1996年   22822篇
  1995年   22451篇
  1994年   21100篇
  1993年   19748篇
  1992年   68219篇
  1991年   65951篇
  1990年   63904篇
  1989年   61048篇
  1988年   56682篇
  1987年   55645篇
  1986年   52892篇
  1985年   50832篇
  1984年   38577篇
  1983年   32618篇
  1982年   20159篇
  1981年   17925篇
  1980年   16977篇
  1979年   35032篇
  1978年   25121篇
  1977年   21192篇
  1976年   19661篇
  1975年   20956篇
  1974年   24828篇
  1973年   23699篇
  1972年   22233篇
  1971年   20487篇
  1970年   19009篇
  1969年   17897篇
  1968年   16841篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
111.
112.
For many parents stopping life-sustaining medical treatment on their dying infant is psychologically impossible. Dostoevsky's insights into human behavior, particularly the fact that individuals do not want the anxiety and guilt associated with responsibility for making difficult decisions, might change the way physicians approach parents for permission to withdraw life-prolonging medical interventions on dying infants.  相似文献   
113.
114.
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   
115.
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   
116.
117.
118.
119.
120.
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   
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