首页 | 官方网站   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   185篇
  免费   4篇
  国内免费   13篇
医药卫生   202篇
  2023年   1篇
  2020年   1篇
  2019年   2篇
  2018年   1篇
  2016年   2篇
  2015年   1篇
  2014年   5篇
  2013年   11篇
  2012年   3篇
  2011年   7篇
  2010年   8篇
  2009年   8篇
  2008年   4篇
  2007年   15篇
  2006年   4篇
  2005年   5篇
  2004年   2篇
  2003年   3篇
  2002年   3篇
  2001年   4篇
  2000年   4篇
  1999年   2篇
  1998年   12篇
  1997年   12篇
  1996年   5篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   7篇
  1991年   1篇
  1990年   1篇
  1989年   4篇
  1988年   5篇
  1987年   6篇
  1986年   5篇
  1985年   1篇
  1984年   5篇
  1983年   3篇
  1982年   6篇
  1981年   1篇
  1980年   5篇
  1979年   1篇
  1977年   3篇
  1976年   1篇
  1975年   2篇
  1971年   1篇
排序方式: 共有202条查询结果,搜索用时 78 毫秒
31.
32.
33.
34.
乏氧细胞对射线所具有的较大抗性是对某些人类肿瘤进行放疗失效的主要原因。放射增敏剂的研究目的是为了提高射线在正常组织可耐受剂量下对肿瘤细胞的杀伤率,从而提高放疗效果。目前试用于临床的放射增散剂misoniizole(MISO)是一种硝基咪唑类化合物,由于其较强的神经毒性,限制了这种药物的推广和使用。为寻找新的低毒有效的放射增敏剂,我们设计并合成了一系列化合物,试验了它们对离体Hela-S_3细胞的放射增敏作用。  相似文献   
35.
刘汇辛  胡璧  李政  糜福顺  沈瑜 《药学学报》1992,27(8):632-637
A series of compounds was synthesized, these compounds were tested for Hela-S3cells in vitro for radiosensitizing activity. Five of them are 2,2′- (arylimino)-diethyl-sodium thio-sulfate and two of them are phenylalanine derivatives. Most of them showed various degrees of ra-diosensitizing activity. Among them, SER of L07 was 1.89 at 3 mmol, and had low cytotoxicity toHela-S3 cells;ID50 was 18.8 mmol. The relationship between radiosensitizing effects and chemicalstructure was discussed. It offers a base for further exploration of selectively hypoxic cell radiosens-itizers.  相似文献   
36.
赤芝子实体中灵芝酸类成分的研究   总被引:16,自引:1,他引:15  
自赤芝[Ganodermalucidum(Fr.)Karst.]子实体的二氯甲烷提取物中分离得到一个新的四环三萜化合物,命名为灵芝酸DM(ganodericacidDM,I)。根据光谱(UV,IR,1HNMR,13CNMR,MS2DNMR)分析,确定其结构为I式。同时还分离得到二个已知的灵芝酸类化合物,即灵芝酸A(ganodericacidA,I)和灵芝酸C(ganodericacidC,II)。  相似文献   
37.
Detectability of breast cancer with magnetic resonance (MR) imaging versus xeromammography was quantitatively compared. MR images were obtained of breasts of 120 women who underwent xeromammography. T1 values were determined for masses larger than 2 cm. Cancer was histologically confirmed in 39 breasts and was considered excluded from 81 due to results of biopsy, cyst aspiration, or sonography or absence of change in xeromammographic findings over time. Images were blindly interpreted by three observers, and results were expressed as receiver operating characteristic curves. Detectability of breast cancer was substantially better with xeromammography than with MR imaging for all observers (P less than .03, 10(-6), and .001). On MR images, spiculation of a mass, distorted architecture, skin thickening, and nipple or skin retraction were specific but relatively insensitive indicators of cancer. Masses with smooth, distinct margins and signal intensity greater than that of fat on T2-weighted images were always benign. Other findings and T1 values were not diagnostically useful. The authors conclude that xeromammography is superior to MR imaging in detection of breast cancer.  相似文献   
38.
BACKGROUND: To investigate the findings and prognosis of rheumatic fever (RF) patients seen in the past 20 years and to compare the last two decades. METHODS: The medical records of all RF patients admitted to Gazi University Department of Pediatric Cardiology during 1982-2002 were reviewed. The decade from 1.1.1982 to 31.12.1991 was designated as 1980s and the following decade as the 1990s. RESULTS: Among the 609 RF cases, there was no difference between the two decades regarding mean age, male/female ratio, most of the minor manifestations and findings of the preceding streptococcal infection. As the rate of carditis declined in 1990s, rates of arthritis and chorea increased. Severity of carditis and admissions with reactivation decreased during 1990s. The two decades did not differ regarding mean age, gender ratio, pericarditis rate, number and type of valvular involvement and sequel of carditis cases. Severity of carditis and number of valvular involvement influenced the first-year prognosis. Almost one-third of the arthritis cases had monoarthritis in both decades. Atypical cases with small-joint involvement were detected number of which increased during the 1990s. CONCLUSIONS: The two decades do not seem to differ regarding most of the manifestations of RF. More emphasis should be given to atypical cases such as small-joint involvement and monoarthritis and silent carditis.  相似文献   
39.
OBJECTIVES: To investigate the relationship of specific nutrients and food items with oral precancerous lesions among tobacco users.
DESIGN: A population-based case-control study. SETTING: Villages in Palitana taluk of Bhavnagar district, Gujarat, India.
SUBJECTS AND METHODS: An interviewer-administered food frequency questionnaire, developed and validated for this population, was used to estimate nutrient intake in blinded, house-to-house interviews. Among 5018 male tobacco users, 318 were diagnosed as cases. An equal number of controls matched on age (±5 years), sex, village, and use of tobacco were selected.
MAIN OUTCOME MEASURES: Odds ratios (OR) from multiple logistic regression analysis controlling for relevant variables (type of tobacco use and economic status).
RESULTS: A protective effect of fibre was observed for both oral submucous fibrosis (OSF) and leukoplakia, with 10% reduction in risk per g day-1 ( P < 0.05). Ascorbic acid appeared to be protective against leukoplakia with the halving of risk in the two highest quartiles of intake (versus the lowest quartile: OR = 0.46 and 0.44, respectively; P < 0.10). A protective effect of tomato consumption was observed in leukoplakia and a suggestion of a protective effect of wheat in OSF.
CONCLUSION: In addition to tobacco use, intake of specific nutrients may have a role in the development of oral precancerous lesions.  相似文献   
40.
树突状细胞与肝脏疾病   总被引:9,自引:3,他引:6  
免疫反应的产生首先是由抗原提呈细胞(antigenpresenting cells,APC)捕获抗原,经其加工处理后将抗原信息传递给T,B淋巴细胞,从而引发一系列的特异性免疫应答.APC包括树突状细胞(dendritic cells,DC)、巨噬细胞(MΦ)、B细胞等,其中DC是人体内最具潜能的抗原提呈细胞(APC),能在体内外直接激活纯真(naive)T细胞,提呈抗原给MHC-Ⅰ类限制性CD8+和MHC-Ⅱ类限制性CD4+T淋巴细胞,诱导特异性免疫应答[1-6].  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-23

京公网安备 11010802026262号