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   761篇
  免费   54篇
  国内免费   8篇
耳鼻咽喉   13篇
儿科学   64篇
妇产科学   5篇
基础医学   94篇
口腔科学   12篇
临床医学   95篇
内科学   141篇
皮肤病学   4篇
神经病学   65篇
特种医学   139篇
外科学   33篇
综合类   17篇
预防医学   56篇
眼科学   6篇
药学   40篇
中国医学   2篇
肿瘤学   37篇
  2022年   7篇
  2021年   8篇
  2020年   9篇
  2019年   5篇
  2018年   5篇
  2017年   2篇
  2016年   9篇
  2015年   10篇
  2014年   14篇
  2013年   18篇
  2012年   19篇
  2011年   16篇
  2010年   15篇
  2009年   21篇
  2008年   16篇
  2007年   22篇
  2006年   20篇
  2005年   26篇
  2004年   20篇
  2003年   17篇
  2002年   21篇
  2001年   12篇
  2000年   11篇
  1999年   13篇
  1998年   45篇
  1997年   63篇
  1996年   44篇
  1995年   35篇
  1994年   37篇
  1993年   28篇
  1992年   16篇
  1991年   15篇
  1990年   10篇
  1989年   24篇
  1988年   24篇
  1987年   23篇
  1986年   21篇
  1985年   25篇
  1984年   9篇
  1983年   6篇
  1982年   11篇
  1981年   6篇
  1980年   8篇
  1979年   2篇
  1978年   9篇
  1977年   8篇
  1976年   6篇
  1975年   6篇
  1959年   1篇
  1955年   1篇
排序方式: 共有823条查询结果,搜索用时 15 毫秒
1.
Correlation studies were performed relating iron availability estimated in vitro using a simulated digestion system to the concentration of protein, sugar, fibre, phytate, ascorbate and citrate in 33 different plant foods. Protein, sugar and fibre showed no significant correlation with iron availability. Phytate was significantly negatively correlated with diffusible iron in cereals, legumes and nuts. Both ascorbate and citrate were highly positively correlated with diffusible iron in vegetables and fruits. It is concluded that iron availability may be related on a quantitative basis to certain components of plant foods.  相似文献   
2.
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   
3.
Paediatric dacryocystorhinostomy   总被引:1,自引:0,他引:1  
Of 258 cases of dacryocystorhinostomy performed on children in the period September 1981 to September 1991, 130 were for simple, unresolved congenital nasolacrimal duct obstruction. Other indications for surgery included punctal agenesis, lacrimal fistula, post-traumatic and post-inflammatory canalicular obstruction. Of 177 children without canalicular pathology, 171 (96%) were relieved of symptoms with one operation, without canalicular intubation. Of 81 cases with canalicular disease, 55 of 70 (79%) who underwent DCR plus canalicular intubation, and 10 of 11 who underwent DCR plus Lester-Jones tube, were substantially improved with one operation. No child required peroperative or postoperative blood transfusion. Dacryocystorhinostomy in childhood, in experienced surgical hands, is a safe procedure, achieving relief of symptoms in most cases, particularly in the absence of canalicular disease.  相似文献   
4.
5.
6.
Factors influencing women to undergo screening mammography   总被引:2,自引:0,他引:2  
  相似文献   
7.
8.
9.
BACKGROUND: There is evidence that the specificity of the IgE binding in allergy tests can vary for different populations. OBJECTIVE: We aimed to examine the allergenic specificity of IgE binding in sera from house dust mite (HDM)-atopic subjects in a tropical Australian Aboriginal community. METHODS: Sera shown to contain IgE antibodies to an HDM extract of Dermatophagoides pteronyssinus were examined for IgE binding to a panel of nine purified HDM allergens from this mite species by quantitative microtitre assays. IgG antibody binding (IgG1 and IgG4) was also measured. RESULTS: The IgE-binding activity in the sera from the Aboriginal community was not directed to the expected major groups 1 and 2 HDM allergens but instead to the group 4 amylase allergen. There was also little IgE binding to the potentially cross-reactive tropomyosin (Der p 10) or arginine kinase (Der p 20) allergens. The IgG4 antibody was rarely detected and limited to the Der p 4 allergen. IgG1 antibody binding was frequently measured to all the allergens regardless of an individual's atopic status, whereas in urban communities it is restricted to the major allergens and to atopic subjects. CONCLUSION: The high IgE anti-HDM response of Australian Aboriginals predominantly bound Der p 4 and not the Der p 1 and 2 allergens, showing a distinctive allergy that could affect the disease outcome and diagnosis.  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