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   10646篇
  免费   655篇
  国内免费   45篇
耳鼻咽喉   238篇
儿科学   785篇
妇产科学   404篇
基础医学   1055篇
口腔科学   290篇
临床医学   955篇
内科学   2224篇
皮肤病学   426篇
神经病学   498篇
特种医学   273篇
外科学   1665篇
综合类   582篇
一般理论   4篇
预防医学   921篇
眼科学   207篇
药学   561篇
  1篇
中国医学   15篇
肿瘤学   242篇
  2021年   68篇
  2018年   57篇
  2017年   78篇
  2016年   63篇
  2015年   92篇
  2014年   106篇
  2013年   172篇
  2012年   234篇
  2011年   244篇
  2010年   175篇
  2009年   208篇
  2008年   183篇
  2007年   195篇
  2006年   204篇
  2005年   168篇
  2004年   125篇
  2003年   107篇
  2002年   141篇
  2001年   154篇
  2000年   139篇
  1999年   162篇
  1998年   182篇
  1997年   210篇
  1996年   241篇
  1995年   178篇
  1994年   184篇
  1993年   174篇
  1992年   155篇
  1991年   164篇
  1990年   151篇
  1989年   158篇
  1988年   149篇
  1987年   159篇
  1986年   145篇
  1985年   117篇
  1984年   103篇
  1983年   92篇
  1982年   73篇
  1981年   82篇
  1980年   75篇
  1979年   62篇
  1977年   55篇
  1959年   343篇
  1958年   760篇
  1957年   870篇
  1956年   771篇
  1955年   803篇
  1954年   780篇
  1949年   183篇
  1948年   125篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
2.
3.
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.
L Disney  B Weir  K Petruk 《Neurosurgery》1987,20(5):695-701
Of 736 patients with intracranial aneurysms seen at the University of Alberta from 1968 to 1985, 437 were admitted on the day of or the day after subarachnoid hemorrhage (SAH) from a supratentorial aneurysm. Of these, 205 were managed from 1968 through 1977 and 232 were managed from 1978 through early 1985 after a policy of early aneurysm operation had been implemented. Postoperative and management mortality and morbidity rates were related to the grade of the patient at the time of admission and the time interval before operation. Overall management mortality (and postoperative mortality) rates for patients treated before 1978 were 47% (19%) for all grades, 17% (12%) for Grades 1 and 2, 51% (25%) for Grades 3 and 4, and 100% (100%) for Grade 5. Since 1978, mortality has been reduced to 38% (11%) for all grades, 10% (5%) for Grades 1 and 2, 39% (17%) for Grades 3 and 4, and 96% (60%) for Grade 5. Management mortality for patients operated on Day 0 to 3 was lower than for those operated later after SAH both before and after 1978. Postoperative mortality was lowered in all patients operated from 1978 to 1985 regardless of the interval from SAH to operation, and management mortality was reduced overall, as well as for patients operated on day 0 to 3, in those treated from 1978 to 1985. The authors conclude that a policy of early aneurysm operation has contributed to a reduction of both postoperative and management mortality.  相似文献   
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