首页 | 官方网站   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   171899篇
  免费   6446篇
  国内免费   315篇
医药卫生   178660篇
  2023年   756篇
  2021年   1229篇
  2020年   1109篇
  2019年   1308篇
  2018年   2849篇
  2017年   2355篇
  2016年   3282篇
  2015年   3660篇
  2014年   3829篇
  2013年   5397篇
  2012年   8365篇
  2011年   7786篇
  2010年   4617篇
  2009年   3721篇
  2008年   7733篇
  2007年   8584篇
  2006年   8614篇
  2005年   9006篇
  2004年   8599篇
  2003年   8498篇
  2002年   8395篇
  2001年   6243篇
  2000年   6312篇
  1999年   5443篇
  1998年   1582篇
  1997年   1308篇
  1996年   998篇
  1995年   814篇
  1994年   752篇
  1992年   2421篇
  1991年   2351篇
  1990年   2308篇
  1989年   2150篇
  1988年   1876篇
  1987年   1877篇
  1986年   1727篇
  1985年   1672篇
  1984年   1299篇
  1983年   1038篇
  1979年   1401篇
  1978年   1017篇
  1977年   854篇
  1975年   1093篇
  1974年   1129篇
  1973年   1042篇
  1972年   1033篇
  1971年   1010篇
  1970年   892篇
  1969年   832篇
  1968年   801篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
51.
52.
Cerebral infarction is rare in premature newborns and is most commonly the result of arterial embolization from the placenta. A focal echodense area was identified on prenatal cranial ultrasonography (US) in a premature infant (34 weeks of gestation). After birth, cerebral infarction was confirmed by magnetic resonance imaging (MRI). The clinical findings, imaging findings and pathogenesis are discussed. New diagnostic methods such as MRI show to be a useful approach in the neonatal period facilitating recognition of cerebrovascular accidents also in low-birth-weight infants.  相似文献   
53.
The authors' 5-year experience in the management and care of prostatic carcinoma are summarized. Their method differs essentially from earlier practice. They have found a new diagnostic and therapeutic method by introducing the TECO irradiation therapy, extensively using bone scintigraphy, by introducing cytostatics, extensively applying the prostate-specific acid phosphatase and by performing rectal biopsy of the prostate. They describe their own observations on the diagnostics and therapy of prostatic carcinoma. They stress that none of the therapies is the method of choice, the use of the various kinds of treatment are defined by strict indications. They state that care of prostatic cancer patients is highly important because only observation of the course of the disease may ensure the evaluation of treatment results and the indication of the adequate therapeutic method.  相似文献   
54.
55.
The atomic rearrangement cascade that follows the electron-capture decay process in low-Z radionuclides involves X-rays which have high photoelectric interaction probabilities. When the K-shell binding energy of the ionized atom (e.g., hydrogen) is significantly lower than the energy of the X-ray photon, the detector response to a photon-equivalent energy electron and the whole photoionization process are very similar. This is not the case when the scintillator cocktail contains larger atoms (e.g., oxygen and phosphorus in Ultima Gold). For larger Z atoms, the reduced energy of the whole photoionization process is less than the reduced energy of the interacting photon due to the nonlinear effects of ionization quenching. This paper shows the convenience of including a more detailed simulation of the photoionization process in the atomic rearrangement detection model for electron-capture nuclides such as (55)Fe, (51)Cr and (54)Mn. The need for more elaborate atomic rearrangement models is a consequence of the analysis of (125)I data.  相似文献   
56.
57.
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   
58.
59.
60.
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-23

京公网安备 11010802026262号