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   10044篇
  免费   412篇
  国内免费   49篇
耳鼻咽喉   216篇
儿科学   780篇
妇产科学   400篇
基础医学   1052篇
口腔科学   282篇
临床医学   933篇
内科学   1941篇
皮肤病学   418篇
神经病学   458篇
特种医学   238篇
外科学   1487篇
综合类   361篇
一般理论   4篇
预防医学   842篇
眼科学   306篇
药学   545篇
  1篇
中国医学   14篇
肿瘤学   227篇
  2021年   58篇
  2018年   57篇
  2017年   75篇
  2016年   74篇
  2015年   105篇
  2014年   112篇
  2013年   168篇
  2012年   221篇
  2011年   229篇
  2010年   184篇
  2009年   208篇
  2008年   167篇
  2007年   182篇
  2006年   176篇
  2005年   145篇
  2004年   92篇
  2003年   87篇
  2002年   89篇
  2001年   101篇
  2000年   84篇
  1999年   132篇
  1998年   185篇
  1997年   212篇
  1996年   226篇
  1995年   184篇
  1994年   172篇
  1993年   167篇
  1992年   129篇
  1991年   137篇
  1990年   129篇
  1989年   151篇
  1988年   122篇
  1987年   120篇
  1986年   105篇
  1985年   78篇
  1984年   82篇
  1983年   64篇
  1982年   54篇
  1981年   63篇
  1980年   47篇
  1978年   44篇
  1977年   51篇
  1959年   343篇
  1958年   759篇
  1957年   868篇
  1956年   771篇
  1955年   803篇
  1954年   781篇
  1949年   182篇
  1948年   125篇
排序方式: 共有10000条查询结果,搜索用时 21 毫秒
1.
2.
The modulation of oxytocin (OT) receptors (OTRs) by estrogen was investigated in the ventromedial hypothalamus by in vitro receptor autoradiography. Treatment of ovariectomized and adrenalectomized rats with various doses of estradiol benzoate (EB) increased OTR binding not only in the ventromedial nuclei of the hypothalamus (VMN), but also in the area lateral to the nuclei (IVMN). After a single injection of EB, OTRs first were induced within the ventrolateral parts of the VMN, and only hours later they appeared in the IVMN. This is consistent with the interpretation that OTRs are first induced within the estrogen-sensitive neurons of the ventrolateral VMN and then are transported laterally out of the nuclei. Two additional experiments confirmed this interpretation. First, local infusion of a low dose (10 micrograms) of the neuronal transport inhibitor vinblastine blocked the appearance of OTRs in the IVMN but did not prevent the induction of OTRs by EB within the nuclei. Second, a knife cut placed lateral to the VMN prevented the spread of OTRs out of the nuclei. However, even after treatment with a high dose of EB (2 x 10 micrograms), progesterone (P) was required for a maximal extension of the area covered by OTRs. Thus, the OTR is an estrogen-induced neurotransmitter receptor that is transported to its site of action, the lateral ventromedial hypothalamus, where it is modulated by P and where estrogen-induced OT immunoreactivity is found.  相似文献   
3.
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   
4.
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   
5.
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   
6.
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   
7.
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