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   2514篇
  免费   147篇
  国内免费   12篇
耳鼻咽喉   16篇
儿科学   67篇
妇产科学   88篇
基础医学   319篇
口腔科学   143篇
临床医学   219篇
内科学   449篇
皮肤病学   21篇
神经病学   191篇
特种医学   274篇
外科学   336篇
综合类   24篇
一般理论   1篇
预防医学   162篇
眼科学   20篇
药学   160篇
中国医学   1篇
肿瘤学   182篇
  2022年   23篇
  2021年   53篇
  2020年   28篇
  2019年   38篇
  2018年   44篇
  2017年   35篇
  2016年   36篇
  2015年   40篇
  2014年   72篇
  2013年   86篇
  2012年   138篇
  2011年   125篇
  2010年   94篇
  2009年   80篇
  2008年   109篇
  2007年   103篇
  2006年   86篇
  2005年   84篇
  2004年   84篇
  2003年   63篇
  2002年   86篇
  2001年   59篇
  2000年   51篇
  1999年   47篇
  1998年   60篇
  1997年   74篇
  1996年   64篇
  1995年   61篇
  1994年   58篇
  1993年   48篇
  1992年   42篇
  1991年   38篇
  1990年   48篇
  1989年   44篇
  1988年   54篇
  1987年   40篇
  1986年   42篇
  1985年   39篇
  1984年   27篇
  1983年   32篇
  1982年   25篇
  1981年   17篇
  1980年   15篇
  1979年   12篇
  1978年   13篇
  1977年   20篇
  1976年   20篇
  1975年   13篇
  1974年   15篇
  1973年   14篇
排序方式: 共有2673条查询结果,搜索用时 15 毫秒
1.
2.
3.
Graft-versus-host disease (GvHD), a major complication of allogeneic bone marrow transplantation, has been ascribed to mature T cells in the graft. Because T cells play an important role in engraftment of the bone marrow and decrease the probability of relapse of leukemia, a treatment strategy was developed to preserve the benefits of T cells in the graft and to control the severe complications of GvHD. This can be accomplished by the genetic modification of donor T cells with a suicide gene that allows their selective in vivo elimination and subsequently the abrogation of GvHD. For clinical benefit the alloreactivity of herpes simplex virus thymidine kinase (HSV-TK) gene-transduced T cells should be retained. Therefore, we investigated the influence of gene transduction and the selection procedure on T cells. We demonstrated that activation and culturing of T cells reduce their capacity to induce lethal GvHD in an allogeneic rat bone marrow transplantation model. Furthermore, positive immunomagnetic selection of gene-transduced T cells resulted in loss of the GvHD-inducing capacity of HSV-TK(+) T cells directly after MACS (magnetic cell sorting) selection; this loss could be recovered by a 1-day expansion of the selected T cells. No effect on alloreactivity was observed to be caused by the gene transduction procedure. Our study resulted in the development of an optimized culture and gene transduction protocol with preservation of T cell alloreactivity. Treatment of transplanted rats with ganciclovir resulted in a rapid reduction in the number of HSV-TK(+) T cells in the peripheral blood and in increased survival of the animals.  相似文献   
4.
Ruggieri  PM; Laub  GA; Masaryk  TJ; Modic  MT 《Radiology》1989,171(3):785-791
The technique and feasibility of magnetic resonance (MR) angiography of intracranial vessels were studied in 35 healthy volunteers. Variations in image orientation, repetition time (TR), and flip angle were evaluated to determine their effects on flow-related enhancement. Gradient modifications--including echo time (TE), motion compensation, bandwidth, and field of view--were also studied in an effort to reduce motion-induced phase shifts. Results indicated that a FISP (fast imaging with steady precession) sequence with a TR of 50 msec, TE of 15 msec, velocity compensation in the read and section-select directions, acceleration compensation in the read direction, anisotropic volume, and a 1.25-mm partition thickness produced three-dimensional angiographic MR images that were accurate and reproducible in the depiction of the major intracranial vessels. Difficulties with field of view, persistent signal void secondary to higher-order motion, and spatial resolution remain major problems requiring additional study.  相似文献   
5.
6.
7.
Human-induced climate change threatens ecosystems and human health on a global scale. In order to withstand the worldwide threats to ecosystems, the concept of sustainable development was introduced during the 1980s. Since then, this concept has been widely applied to guide and focus policy-making. The present article reviews the health consequences of human-induced climate change on sustainable development, particularly the potential impact of such change of food supply, natural disasters, infectious diseases, ecosystems, and sea level rise. Discussed is an integrated model containing the key indicators of sustainable development. The relevance of climate change, human health, and sustainable development for international climate change policy is also examined.  相似文献   
8.
Neuropeptide signals and specific neuropeptide receptors have been described in the thymus supporting the concept of a close dialogue between the neuroendocrine and the immune systems at the level of early T-cell differentiation. In this paper, we review recent data about neurohypophysial (NHP)-related peptides detected in the thymus from different species. We suggest that we are dealing in fact with other member(s) of the NHP hormone family, which seems to exert its activity locally through a novel model of cell-to-cell signaling, that of cryptocrine communication. This model involves exchange of signals between thymic epithelial cells and developing thymocytes. The NHP-related peptides have been shown to trigger thymocyte proliferation and could induce immune tolerance of this highly conserved neuroendocrine family.  相似文献   
9.
Summary The efficacy and safety of local action transcutaneous flurbiprofen 40 mg [flurbiprofen LAT] patches and diclofenac sodium tablets, 50 mg b.d., were compared in an open, multicentre, randomized, parallel-group study in patients with soft-tissue rheumatism. Patches were replaced at 12-hourly intervals. Clinical assessments were performed after 7 and 14 days of treatment. Fifty-six patients were treated with flurbiprofen LAT and 53 with diclofenac. Six withdrawals (three from each group) occurred during the treatment period.A statistically significant difference was observed in favour of flurbiprofen LAT for the principal measure, namely the investigator's opinion of overall change in clinical condition: 49/53 (92%) patients treated with flurbiprofen LAT had improved by day 14 compared with 36/49 (73%) patients receiving diclofenac sodium (p=0.03; eligible dataset). There were also statistically significant differences in favour of flurbiprofen LAT for the investigator's assessments of the overall severity of the clinical condition (p=0.03; eligible dataset), for the severity of pain at the region treated (p=0.04; intent-to-treat), and for the severity of tenderness (p<0.001; intent-to-treat). Supplementary analgesia (paracetamol) was required by two patients in the flurbiprofen LAT group and by eight diclofenac-treated patients. The difference in favour of flurbiprofen LAT group and by eight diclofenac-treated patients. The difference in favour of flurbiprofen LAT in the average daily consumption of paracetamol was significant (p=0.04). The patients' assessment of severity of pain on movement also favoured flurbiprofen LAT (p =0.049; eligible dataset), but there were no statistically significant differences in day or night pain or quality of sleep. For the patients' opinion of treatment there was, however, a statistically significant difference in favour of flurbiprofen LAT (p=0.02). Of the patients receiving flurbiprofen LAT, 94% regarded it as a convenient form of treatment.With respect to tolerability 8/56 (14%) patients applying flurbiprofen patches reported a total of nine adverse effects (AEs) (mainly local, mild skin irritations), vs 9/52 (17%) patients receiving diclofenac, who reported 12 AEs. Most AEs in the enteric-coated diclofenac group were of a gastrointestinal nature (one of which was severe). In terms of the proportion of patients reporting AEs related to the digestive system, there was a statistically significant difference in favour of flurbiprofen LAT (p=0.011).In conclusion, local treatment of soft-tissue rheumatism with flurbiprofen LAT was demonstrably superior to benchmark oral therapy with diclofenac sodium over a 2-week period in terms of both efficacy and gastrointestinal tolerability. Flurbiprofen LAT provided both an effective and convenient form of topical SAID treatment.  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