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   367篇
  免费   27篇
  国内免费   4篇
耳鼻咽喉   1篇
儿科学   13篇
妇产科学   3篇
基础医学   34篇
口腔科学   4篇
临床医学   20篇
内科学   64篇
皮肤病学   13篇
神经病学   7篇
特种医学   49篇
外科学   36篇
综合类   13篇
预防医学   36篇
药学   42篇
肿瘤学   63篇
  2023年   1篇
  2021年   3篇
  2020年   2篇
  2019年   1篇
  2017年   1篇
  2016年   2篇
  2015年   6篇
  2014年   5篇
  2013年   7篇
  2012年   5篇
  2011年   8篇
  2010年   13篇
  2009年   16篇
  2008年   9篇
  2007年   10篇
  2006年   20篇
  2005年   13篇
  2004年   22篇
  2003年   5篇
  2002年   10篇
  2001年   9篇
  2000年   10篇
  1999年   9篇
  1998年   25篇
  1997年   18篇
  1996年   14篇
  1995年   9篇
  1994年   9篇
  1993年   10篇
  1992年   14篇
  1991年   8篇
  1990年   14篇
  1989年   14篇
  1988年   11篇
  1987年   5篇
  1986年   7篇
  1985年   6篇
  1984年   7篇
  1983年   4篇
  1982年   4篇
  1981年   7篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1977年   5篇
  1976年   6篇
  1975年   4篇
  1972年   2篇
  1966年   1篇
排序方式: 共有398条查询结果,搜索用时 15 毫秒
21.
Administration of BRL 26314 [N-(4-chlorobenzyl)-L-phenylalanine] raises circulating high-density lipoprotein (HDL) cholesterol and lowers total triglyceride levels in rats whether maintained on stock or semi-synthetic diets. HDL is also elevated by BRL 26314 in hypothyroid rats and in rats with pre-existing hyperlipidaemia where aortic total cholesterol concentration is decreased. BRL 26314 promotes the excretion of a dose of radiolabelled cholesterol as faecal sterols and bile acids, and decreases the extent of cholesterol-radiolabelling in tissue pools, particularly the aorta and adipose tissue. The increase in cholesterol and bile acid (cholic acid) turnover distinguishes BRL 26314 from a cholestatic agent such as 1-naphthyl isothiocyanate where a superficially similar change in HDL concentration disguises an impaired cholesterol transport. BRL 26314 is not a general protein inducer but part of the mechanism of action may involve enhancement of white adipose tissue lipoprotein lipase activity.  相似文献   
22.
The development and evaluation of experimental designs for routine in vivo screening of chemicals for potential carcinogenic activity were considered. Such designs have played an important role in the Carcinogenesis Bloassay Program of the National Cancer Institute (NCI). In particular, the current one-stage 50-animal/group screen used by the NCI was considered. A specific two-stage alternative was proposed in which 35 animals/group were used; this alternative allowed for retesting of equivocal compounds. The proposed designs were evaluated in terms of sensitivity, specificity, and throughout. Despite the large number of tests made for each compound, the false-positive rate was found to be less than 0.07 for the current screen and less than 0.05 for the proposed two-stage alternative. The power of the one-stage and two-stage screens was comparable. The two-stage screen was shown to make about 30% more decisions per test period with a savings of around 28% in the expected number of animals needed per compound tested.  相似文献   
23.
24.
25.
The Roman Empire of the second century was a superpower that, in relative terms, dominated its world as much as the United States does today. In 166 AD, a plague broke out od pandemic proportions. The pandemic ravaged the entire extent of the Roman Empire, from its eastern frontiers in Iraq to its western frontiers on the Rhine River and Gaul, modern France, and western Germany. The disease is identified most often as smallpox, but it may have been anthrax. The study of bacterial DNA may enable identification of this plague that ravaged the Roman Empire at recurrent intervals for more than 100 years and that had a significant role in the decline and fall of this great superpower.  相似文献   
26.
Repovic P  Fears CY  Gladson CL  Benveniste EN 《Oncogene》2003,22(50):8117-8124
Oncostatin-M (OSM), a hematopoietic cytokine, and vascular endothelial growth factor (VEGF), a quintessential angiogenic signal, are coexpressed in development, cancer and inflammation. Here, we report that OSM treatment of human astroglioma cell lines increases VEGF levels by approximately threefold. Interleukin-1beta (IL-1beta), in combination with OSM, induces up to sevenfold higher VEGF expression, without significantly inducing VEGF on its own. Specifically examining the OSM contribution to VEGF expression, neutralizing antibodies to OSM receptor subunits gp130 and OSMRbeta, but not LIFRbeta, inhibited OSM induction of VEGF, indicating that the OSM-specific receptor OSMRbeta/gp130 transduces the OSM signal for VEGF synthesis. OSM induction of VEGF promoter activity maps to the (-1171, -786) region of the VEGF promoter, which contains a STAT-3-binding site. STAT-3 is indeed essential for this response, since overexpression of a dominant-negative STAT-3 blocks OSM induction of VEGF promoter activity, as well as endogenous VEGF expression. Finally, we demonstrate that OSM is expressed in glioblastoma multiforme tumor biopsies, a particularly malignant form of brain tumor. This novel mechanism of VEGF regulation in astroglioma cells may be active in pathophysiological states where both OSM and IL-1beta are present.  相似文献   
27.

Background

Phaconit or ultra micro incision phacoemulsification cataract surgery involves phacoemulsification through a 0.9 millimetre sleeveless phaco tip and irrigating chopper followed by implantation of a rollable intraocular lens. The procedure leads to negligible astigmatism and faster visual recovery as compared to phacoemulsification with a foldable intraocular lens.

Methods

This prospective study analysed 80 cases of sub millimetre phaconit surgery with implantation of rollable intraocular lenses(IOL) in 40 cases and acrylic foldable IOL in the remaining 40 cases. Evaluation of efficacy and adaptability of procedure, equipment settings, operative constraints, postoperative complications, keratometric and topographic evaluation of induced astigmatism with visual outcome and patient''s rehabilitation were studied.

Results

The intraoperative complications were surge/ chamber collapse in 16 (20%), iris chaffing in one and corneal burns in two cases. All cases had an induced astigmatism of less than or equal to ± 0.25 D in four to six weeks after rollable IOL and ± 0.5 D to ± 0.75 D after acrylic IOL implantation. All patients had best-corrected visual acuity of 6/6 by third post operative day.

Conclusion

Phaconit with rollable IOL is a perfect blend of surgical skill, application of technology and ultra thin IOL.Key Words: Phaconit, Ultra micro phaco, Submillimetre incision, Rollable IOL implantation  相似文献   
28.
To determine the pathways between treatment intensity (age at diagnosis, dosage of chemotherapy [intrathecal methotrexate; IT-MTX] and cranial radiation [CRT]) and various psychosocial outcomes, review of medical records and structured interviews were carried out in 510 adult survivors of childhood leukemia. Structural equation modeling revealed that higher treatment intensity during childhood (indicated by treatment with high-dose CRT, low-dose IT-MTX, and adjusted by younger age at diagnosis) predicted more health- compromising behaviors as adults through lower educational achievement. Additionally, higher childhood treatment intensity predicted current negative mood both directly and via changes in perceived limitations. The present study's findings suggest that higher treatment intensity during childhood may serve as a risk factor for adult survivors' health-compromising behaviors through neuropsychological deficits that arise from cancer treatment.  相似文献   
29.
30.
A group of girls is described with recurrent urinary tract infections characterized by predominantly lower tract symptoms. Clinical, laboratory, and radiography findings during the period of follow-up are presented. Infection persisted in most patients over several years. Response to medical and surgical treatment was unsatisfactory. The mean interval between the initial and most recent radiological study was 6 1/2 years. No case of renal parenchymal scarring was seen.  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