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   10088篇
  免费   416篇
  国内免费   40篇
耳鼻咽喉   202篇
儿科学   807篇
妇产科学   500篇
基础医学   1013篇
口腔科学   227篇
临床医学   822篇
内科学   1904篇
皮肤病学   546篇
神经病学   404篇
特种医学   207篇
外科学   1486篇
综合类   335篇
一般理论   2篇
预防医学   1015篇
眼科学   263篇
药学   519篇
  1篇
中国医学   13篇
肿瘤学   278篇
  2021年   51篇
  2018年   56篇
  2017年   66篇
  2016年   68篇
  2015年   87篇
  2014年   103篇
  2013年   161篇
  2012年   187篇
  2011年   201篇
  2010年   171篇
  2009年   188篇
  2008年   171篇
  2007年   177篇
  2006年   201篇
  2005年   146篇
  2004年   95篇
  2003年   72篇
  2002年   109篇
  2001年   98篇
  2000年   85篇
  1999年   107篇
  1998年   177篇
  1997年   200篇
  1996年   228篇
  1995年   183篇
  1994年   181篇
  1993年   176篇
  1992年   158篇
  1991年   144篇
  1990年   143篇
  1989年   137篇
  1988年   119篇
  1987年   137篇
  1986年   118篇
  1985年   90篇
  1984年   90篇
  1983年   84篇
  1982年   73篇
  1981年   72篇
  1980年   55篇
  1979年   58篇
  1977年   62篇
  1959年   343篇
  1958年   762篇
  1957年   870篇
  1956年   776篇
  1955年   804篇
  1954年   782篇
  1949年   186篇
  1948年   126篇
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
2.
3.
The carpal regions of ten cadaver extremities were imaged by CT. The images were combined into a 3-dimensional model of the carpus using a technique based on a dynamic programming algorithm to find an optimal estimate of the location of the bone boundaries in the CT images. The resulting set of surface points on each bone was used to compute volumes and principal and antipodal axes for the bones. A spatial coordinate system was established based on the positions of the centroids of three bones in the distal carpal row. The angular orientations of all carpal bones were determined with respect to this system. The principal axes for the same bone among ten wrist specimens proved to be more widely dispersed than the antipodal axes for the same bones. The antipodal axes also correspond more closely to an intuitive notion of the “longest axis” of the bones. We conclude that the antipodal axis is a more reliable and useful measure of bone orientation than the principal axis.  相似文献   
4.
Restriction fragment length polymorphism (RFLP) of human mitochondrial DNA was analysed in a sample of 87 subjects from Apulia (South Italy) by the restriction enzymes Hpa I, Bam HI, Hae II, Msp I, Ava II, and Hinc II using total blood cell DNA probed by human mtDNA from placenta. Five BamHI morphs were observed, two of which are new ( Bam HI-4 and -5), as well as one new Ava II morph ( Ava II-28). The association Bam HI-4/ Ava II-28 enables us to demonstrate for the first time two polymorphic Bam HI sites present together in the same mtDNA molecule. In agreement with historical data the Apulian sample has been shown to be the most heterogeneous Italian population so far tested.  相似文献   
5.
The synthesis of TPH-13 (Glp-Glu-Lys-Pro-Tyr-Trp-Pro-Pro-Pro-Ile-Tyr-Pro-Met-OH), a tridecapeptide isolated from the skin of the South American frog Phyllomedusa rohdei, is described and alternative approaches are discussed.  相似文献   
6.
Intratemporal vascular tumors: detection with CT and MR imaging   总被引:1,自引:0,他引:1  
The diagnostic contributions of computed tomography (CT) and magnetic resonance (MR) imaging were compared in 12 patients with benign intratemporal vascular tumors (hemangioma or vascular malformation). The tumors included six in the internal acoustic canal and six in the geniculate ganglion region. Clinical and histologic correlations were made. Two of the six patients with tumors in the internal acoustic canal underwent CT, and both required gas cisternography to show the tumor. Five patients in that group underwent MR imaging, and all five studies showed the tumor. All six patients with geniculate ganglion tumors underwent CT. Results in one study were questionable, and five showed the tumor. Five patients in this group underwent MR imaging, but the MR findings were positive in only two cases. MR imaging should therefore be performed before CT in the evaluation of facial nerve dysfunction, as it demonstrated all tumors in the internal acoustic canal and some in the geniculate ganglion region. If MR findings are negative, CT should then be performed to rule out a possible geniculate ganglion lesion.  相似文献   
7.
Abstract:  In Sweet's syndrome, the essential features are the characteristic morphology of the lesions, their histologic appearance, the dramatic response to corticosteroids and the absence of scarring. We report an 8-month-old infant in whom Sweet's syndrome was diagnosed and who developed acquired cutis laxa in the skin lesions.  相似文献   
8.
9.
10.
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