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   5112篇
  免费   468篇
  国内免费   41篇
耳鼻咽喉   51篇
儿科学   200篇
妇产科学   132篇
基础医学   513篇
口腔科学   127篇
临床医学   518篇
内科学   1112篇
皮肤病学   159篇
神经病学   367篇
特种医学   264篇
外国民族医学   5篇
外科学   902篇
综合类   210篇
现状与发展   30篇
一般理论   1篇
预防医学   302篇
眼科学   86篇
药学   304篇
中国医学   34篇
肿瘤学   304篇
  2024年   16篇
  2023年   210篇
  2022年   96篇
  2021年   158篇
  2020年   149篇
  2019年   134篇
  2018年   192篇
  2017年   130篇
  2016年   139篇
  2015年   169篇
  2014年   245篇
  2013年   245篇
  2012年   278篇
  2011年   314篇
  2010年   254篇
  2009年   244篇
  2008年   219篇
  2007年   253篇
  2006年   219篇
  2005年   256篇
  2004年   199篇
  2003年   185篇
  2002年   166篇
  2001年   84篇
  2000年   81篇
  1999年   103篇
  1998年   60篇
  1997年   75篇
  1996年   56篇
  1995年   63篇
  1994年   45篇
  1993年   53篇
  1992年   34篇
  1991年   25篇
  1990年   33篇
  1989年   42篇
  1988年   38篇
  1987年   31篇
  1986年   27篇
  1985年   30篇
  1984年   18篇
  1983年   15篇
  1982年   22篇
  1981年   20篇
  1980年   20篇
  1978年   25篇
  1976年   23篇
  1975年   17篇
  1972年   13篇
  1969年   15篇
排序方式: 共有5621条查询结果,搜索用时 250 毫秒
1.
2.
Anaphylaxis     
A 60 year old man attends to discuss his recent allergic reaction to an insect sting. He presents you with the casualty letter which reads : " Treated for anaphylaxis after bee sting-see GP for follow-up. "  相似文献   
3.
Central post stroke pain is often difficult to manage satisfactorily with conventional treatment modalities for pain. In the last decade functional neurosurgery has offered hope with motor cortex stimulation achieving significant alleviation of pain in some patients. Unfortunately this has led to the neglect of chronic stimulation of deep grey matter as another modality of treating this condition. In this article we present our experience with motor cortex stimulation and that with deep grey matter stimulation in patients with post stroke pain. We argue that both modalities have a significant role and that what is required are better methods of identifying particular patients who are more likely to respond to one or the other.  相似文献   
4.
5.
6.
Hysterosalpingography was performed in 31 patients by means of a low-dose scanning-beam digital radiographic system. The technique permits adequate evaluation of gynecologic abnormalities while allowing significant reduction in radiation: 2.4-mR (6.1 X 10(-7) C/kg) exposure to the skin and 0.7-mrad (7 X 10(-6) Gy) mean dose to the ovaries per image obtained. Sixteen patients demonstrated readily recognizable and documented abnormalities, corroborated by laparoscopy, laparotomy, or other supportive evidence.  相似文献   
7.
Overexpression of wound healing-promoting factors such as transforming growth factor-1 (TGF-beta1) and insulin-like growth factor-1 (IGF-1) during the healing process has been implicated in the development of dermal fibrosis in patients following thermal injury, surgical incision, and deep trauma. However, the mechanism through which the expression of these two fibrogenic factors is slowed down and/or abrogated in the late stages of the healing process is not known. Here, we hypothesize that keratinocyte-releasable factors counteract the fibrogenic role of both IGF-1 and TGF-beta1 in fibroblasts. To test this hypothesis, the levels of collagenase (MMP-1), as an index for extracellular matrix degradation, in dermal fibroblasts in response to either keratinocyte-conditioned medium (KCM) or our recently identified keratinocyte-releasable stratifin in the presence and absence of either IGF-1, TGF-beta1, or both were evaluated. The results of Northern analysis showed a significant increase in collagenase mRNA expression in cells treated with KCM in the presence of both IGF-1 and TGF-beta1. The effect was, at least in part, due to keratinocyte-derived stratifin that was present in KCM. This was ascertained as the levels of MMP-1 mRNA were markedly reduced when cells were treated with stratifin-immuno-depleted KCM. The results of Western blot analysis showed an increase in the level of MMP-1 protein in stratifin-treated fibroblasts and this was consistent with the level of MMP-1 mRNA expression detected by Northern analysis. However, in contrast to KCM, whose efficacy on MMP-1 expression was modestly reduced by either IGF-1 and TGF-beta1, or a combination of both, these factors abrogated the MMP-1 stimulatory effect of stratifin in fibroblasts. In summary, the results of this study revealed that both stratifin and KCM stimulate the expression of MMP-1-in fibroblasts and this effect can be abrogated by either IGF-1, TGF-beta1, or a combination of both.  相似文献   
8.
9.
This paper presents our initial experience utilizing a new technique which allows CT and MR image fusion in patients with skull base lesions. Eleven patients with a variety of skull base lesions underwent CT and MR imaging prior to surgery. Both sets of images were coregistered using customized software. The CT and MR data sets were then combined and viewed in a single interactive image formar using a high-speed graphic computing system. Image fusion allowed simultaneous visualization of the bony skull base anatomy (CT) and detailed soft tissue anatomy (MR) using a single image format. Combining both modalities was felt to provide a better assessment of the extent of lesions and improve understanding of their relationship to adjacent bony and neurovascular anatomy. Specifically, image fusion enhanced awareness of location of skill base lesions with respect to the cavernous sinuses. Gasserian ganglia, carotid arteries, and jugular foramina. For tumors arising within the internal auditory canal (IAC), fused images allowed better delineation of the lateral aspect of the lesion with respect to the fundus of the IAC. Thus, fusion of CT and MR studies provides a unique image format which has advantages over single modality display. We believe image fusion is beneficial for surgical planning and for treatment planning of complex skull base malignancies treated with radiotherapy.  相似文献   
10.
A review of factors contributing to early mortality after cardiac transplantation revealed that up to 25 % of deaths were due to primary graft dysfunction unrelated to rejection or infection. In light of this finding, evaluation of a donor heart with regard to its suitability for transplantation takes on added importance. In an effort to screen the suitability of donor hearts in the region covered by the Northwest Organ Procurement Agency (USA), all donors are evaluated by two-dimensional transthoracic echocardiography as part of the initial evaluation. A total of 110 donor echocardiograms were reviewed and an attempt was made to correlate the 30-day outcome with the parameters measured. An unexpected finding was that the presence of left ventricular hypertrophy in the donor heart was associated with an increase in the incidence of donor heart dysfunction compared with donors with normal echocardiographic profiles (33 % vs 3 %, P = 0.007). Received: 12 February 1996 Received after resision: 27 June 1997 Accepted: 14 July 1997  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