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   568篇
  免费   35篇
  国内免费   7篇
耳鼻咽喉   2篇
儿科学   32篇
妇产科学   2篇
基础医学   52篇
口腔科学   33篇
临床医学   47篇
内科学   124篇
皮肤病学   17篇
神经病学   10篇
特种医学   99篇
外科学   68篇
综合类   24篇
预防医学   35篇
眼科学   4篇
药学   45篇
中国医学   1篇
肿瘤学   15篇
  2021年   16篇
  2020年   4篇
  2019年   1篇
  2018年   6篇
  2017年   4篇
  2016年   11篇
  2015年   10篇
  2014年   12篇
  2013年   27篇
  2012年   24篇
  2011年   8篇
  2010年   25篇
  2009年   27篇
  2008年   14篇
  2007年   11篇
  2006年   23篇
  2005年   12篇
  2004年   9篇
  2003年   15篇
  2002年   11篇
  2001年   10篇
  2000年   10篇
  1999年   22篇
  1998年   35篇
  1997年   25篇
  1996年   21篇
  1995年   13篇
  1994年   22篇
  1993年   23篇
  1992年   8篇
  1991年   8篇
  1990年   6篇
  1989年   13篇
  1988年   15篇
  1987年   10篇
  1986年   14篇
  1985年   7篇
  1984年   8篇
  1983年   6篇
  1982年   9篇
  1981年   12篇
  1980年   12篇
  1978年   4篇
  1977年   5篇
  1976年   12篇
  1975年   4篇
  1974年   2篇
  1970年   1篇
  1957年   1篇
  1955年   1篇
排序方式: 共有610条查询结果,搜索用时 15 毫秒
101.
Discoid lupus erythematosus is a manifestation of chronic cutaneous lupus erythematosus with a small risk of systemic involvement. In this review article, the role of predisposing factors such as haplotype, hormones, antibodies and sunlight are discussed. The clinical features, including variants and associations, and management options are presented.  相似文献   
102.
103.
Summary. Background: The European Network of Rare Bleeding Disorders (EN‐RBD) was established to bridge the gap between knowledge and practise in the care of patients with RBDs. Objectives: To explore the relationship between coagulation factor activity level and bleeding severity in patients with RBDs. Patients/Methods: Cross‐sectional study using data from 489 patients registered in the EN‐RBD. Coagulation factor activity levels were retrieved. Clinical bleeding episodes were classified into four categories according to severity. Results: The mean age of patients at data collection was 31 years (range, 7 months to 95 years), with an equal sex distribution. On linear regression analysis, there was a strong association between coagulation factor activity level and clinical bleeding severity for fibrinogen, factor (F) X, FXIII, and combined FV and FVIII deficiencies. A weaker association was present for FV and FVII deficiencies. There was no association between coagulation factor activity level and clinical bleeding severity for FXI. The coagulation factor activity levels that were necessary for patients to remain asymptomatic were: fibrinogen, > 100 mg dL?1; FV, 12 U dL?1; combined FV + VIII, 43 U dL?1; FVII, 25 U dL?1; FX, 56 U dL?1; FXI, 26 U dL?1; FXIII, 31 U dL?1. Moreover, coagulation factor activity levels that corresponded with Grade III bleeding were: undetectable levels for fibrinogen, FV and FXIII, < 15 U dL?1 for combined FV + VIII; < 8 U dL?1 for FVI; < 10 U dL?1 for FX; and < 25 U dL?1 for FXI. Conclusions: There is a heterogeneous association between coagulation factor activity level and clinical bleeding severity in different RBDs. A strong association is only observed in fibrinogen, FX and FXIII deficiencies.  相似文献   
104.
由于血小板只有5天的保存期,库存压力导致经常输注ABO血型不合的血小板.为了避免血小板过期,首先输注的是库存时间最长的血小板,包括输注ABO血型不合的血小板.AABB和英国血液学标准委员会建议,输注红细胞时必须要求ABO主侧相合,而输注血小板并没有要求ABO血型匹配.  相似文献   
105.
106.
107.
108.
Cryptosporidium is a leading global cause of waterborne disease, with many reported outbreaks related to main water supplies. In August 2019, an outbreak of cryptosporidiosis involving 80 cases occurred among 114 vacationers in a small municipality located in the Tuscan-Emilian Apennines, north-eastern Italy. After excluding a potential food-borne outbreak, the epidemiological investigation focussed on the hypothesis of a waterborne outbreak. This was confirmed by the finding of Cryptosporidium oocysts in stools of the cases and in water samples from the municipal water network. Molecular characterisation revealed the zoonotic species Cryptosporidium parvum as the causative agent. A single subtype (IIdA25G1) was found among all cases, and in one of two positive water samples. The municipality’s water supply used spring water that only received a disinfection treatment insufficient to inactivate the parasite. Possible entry means into the water mains were found through further environmental investigations. As these types of water supplies are particularly vulnerable to various environmental factors, a control system based on the risk assessment of each phase of the water supply chain is required to guarantee water safety. Effective methods for detection of protozoan pathogens, which are generally excluded from routine water supply analysis, should be applied.  相似文献   
109.
Summary— The suggestion that adenosine may have beneficial effects on post reperfusion survival following cardiac ischaemia has led to the search for agents which increase the concentration of this substance in the ischemic region as a possible therapeutic approach to the treatment of angina and myocardial infarction. In the present study, dipyridamole, soluflazine and lidoflazine, known inhibitors of the nucleotide exchange system, have been shown using an HPLC method to prevent the decrease in the concentration od added adenosine outside human red blood cells in vitro. However, the results suggest that this effect was due to inhibition of adenosine deaminase rather than inhibition of nucleotide exchange as had previously been suggested. The selective inhibitor of adenosine deaminase erythro-9-(2 hydroxy-3-nonyl adenosine) exhibited the same profile of activity in the human red blood cell assay. pIC50 values for the four compounds named above were found to be 6.80 ± 0.09, 6.95 ± .03, 6.10 ± 0.14 and 7.39 ± 0.05 vs adenosine disapearance observed in the extracellular incubation medium respectively. Thus, as the disappearance of adenosine outside the cells was not due to its uptake but to its catabolism, this in vitro method does not appear to be predictive for the ability of compounds to act on adenosine uptake into cardiac myocytes. Any antiischemic action of these agents is more readily explained by an inhibition of the catabolism of adenosine and not by the inhibition of its transport across the membrane of cardiac myocytes.  相似文献   
110.
白头翁中毛莨甙及合成毛茛甙的高效液相色谱测定法   总被引:1,自引:0,他引:1  
张秀琴  刘爱茹  徐礼燊 《药学学报》1990,25(12):932-935
白头翁为毛莨科属植物Pulsatilla chinensis,以根入药,其煎剂能抑制阿米巴原虫的生长、杀灭阴道滴虫等作用,用于细菌性痢疾和阿米巴痢疾的治疗。白头翁中主要成分有原白头翁素[protoanemonin,系由毛莨甙(ranunculin)酶解而得]、白头翁素(anemonin)等,其结构如下:  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