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   909篇
  免费   35篇
  国内免费   3篇
儿科学   72篇
妇产科学   11篇
基础医学   91篇
口腔科学   25篇
临床医学   83篇
内科学   222篇
皮肤病学   21篇
神经病学   18篇
特种医学   250篇
外科学   38篇
综合类   10篇
预防医学   33篇
眼科学   4篇
药学   27篇
中国医学   1篇
肿瘤学   41篇
  2023年   2篇
  2022年   2篇
  2021年   2篇
  2020年   1篇
  2018年   11篇
  2017年   10篇
  2016年   7篇
  2015年   10篇
  2014年   16篇
  2013年   14篇
  2012年   15篇
  2011年   10篇
  2010年   33篇
  2009年   40篇
  2008年   23篇
  2007年   16篇
  2006年   19篇
  2005年   14篇
  2004年   11篇
  2003年   15篇
  2002年   12篇
  2001年   9篇
  2000年   5篇
  1999年   11篇
  1998年   49篇
  1997年   67篇
  1996年   49篇
  1995年   40篇
  1994年   51篇
  1993年   51篇
  1992年   11篇
  1991年   11篇
  1990年   11篇
  1989年   36篇
  1988年   40篇
  1987年   28篇
  1986年   29篇
  1985年   27篇
  1984年   11篇
  1983年   21篇
  1982年   17篇
  1981年   18篇
  1980年   21篇
  1979年   3篇
  1978年   8篇
  1977年   12篇
  1976年   9篇
  1975年   17篇
  1973年   1篇
  1948年   1篇
排序方式: 共有947条查询结果,搜索用时 61 毫秒
91.
ObjectiveTo determine the knowledge of HIV/AIDS among primary school pupils in north central area of Nigeria.Methods2000 randomly selected primary school pupils in and around eastern part of Idoma area of Benue state were interviewed using an open-ended questionnaire. Data analysis was done with EPI-INFO 2000. The Chi-square test was used for statistical analysis and the 0.05 level of significance was adopted.ResultsA totle of 1010 males and 990 females at ages between five and sixteen years were drawn from 10 primary schools in the area. Pupils in the higher classes were more knowledgeable and sex difference was not statistically significant. Certain misconceptions were noted.ConclusionsThere is need for health education for all cadres of primary school pupils in the area, which will increase the awareness of the disease.  相似文献   
92.
Cytokine production by primary bone marrow megakaryocytes   总被引:4,自引:2,他引:4  
Jiang  S; Levine  JD; Fu  Y; Deng  B; London  R; Groopman  JE; Avraham  H 《Blood》1994,84(12):4151-4156
Primary human bone marrow megakaryocytes were studied for their ability to express and release cytokines potentially relevant to their proliferation and/or differentiation. The purity of the bone marrow megakaryocytes was assessed by morphologic and immunocytochemical criteria. Unstimulated marrow megakaryocytes constitutively expressed genes for interleukin-1 beta (IL-1 beta), IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor-alpha (TNF-alpha), by the polymerase chain reaction (PCR) and Northern blot analysis. At the protein level, megakaryocytes secreted significant amounts of IL-1 beta (53.6 +/- 3.6 pg/mL), IL-6 (57.6 +/- 15.6 pg/mL), and GM-CSF (24 +/- 4 pg/mL) but not TNF-alpha. Exposure of human marrow megakaryocytes to IL-1 beta increased the levels of IL-6 (87.3 +/- 2.3 pg/mL) detected in the culture supernatants. Transforming growth factor- beta was also able to stimulate IL-6, IL-1 beta, and GM-CSF secretion, but was less potent than stimulation with phorbol-12-myristate-13- acetate (PMA). The secreted cytokines acted additively to maintain and increase the number of colony-forming unit-megakaryocytes colonies (approximately 35%). These studies demonstrate the production of multiple cytokines by isolated human bone marrow megakaryocytes constitutively or stimulated in vitro. The capacity of human megakaryocytes to synthesize several cytokines known to modulate hematopoietic cells supports the concept that there may be an autocrine mechanism operative in the regulation of megakaryocytopoiesis.  相似文献   
93.
A patient with cystic kidney disease of adult onset and severecystic hepatomegaly is presented. The patient was severely disabledsolely by her abdominal bulk. Simultaneous liver and renal transplantationwas undertaken successfully.  相似文献   
94.
Balazovich  KJ; Smolen  JE; Boxer  LA 《Blood》1986,68(4):810-817
Ca2+-dependent and phospholipid-dependent protein kinase (PKC) is a receptor for and is activated by phorbol esters. This enzyme is reportedly involved in the mechanism of superoxide anion (O2-) production and the release of intracellular granule contents from human neutrophils. As previously reported by others, we found that greater than 75% of the total cellular PKC activity existed in a soluble form in untreated neutrophils and that this activity was enhanced in a dose- dependent manner by phorbol 12-myristate 13-acetate (PMA) and by phorbol 12,13-dibutyrate (PDBu). Furthermore, mezerein, an analogue of PMA that is thought to be a competitive inhibitor, did not activate PKC, and on the contrary, inhibited PMA-stimulated activity in a dose- dependent manner. Pretreatment of intact neutrophils with PMA or PDBu caused the "translocation" of PKC activity to the insoluble cell fraction; PKC translocation was not detected after mezerein stimulation at any of the tested concentrations. Neither did mezerein cause an increase in intracellular Ca2+, as monitored by Quin 2 fluorescence. Both phorbol esters and mezerein stimulated intact neutrophils to generate O2- and release lysosomal enzymes into the extracellular medium. Finally sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis demonstrated key differences in the patterns of endogenous phosphoproteins of neutrophils stimulated with phorbol as compared with mezerein. We therefore suggest that PKC activation may not be the only pathway required to elicit neutrophil responses.  相似文献   
95.
96.
97.
The conditioning of fear responses to a simple acoustic stimulus (pure tone) paired with footshock can be mediated by the transmission of auditory information to the lateral nucleus of the amygdala from either the auditory thalamus or the auditory cortex. We examined the processing capacity of the thalamo-amygdala pathway by making lesions of the auditory cortex and testing the extent to which conditioned fear responses generalized to tones other than the one paired with footshock. Two studies were performed, one in an anatomically constrained computational model of the fear conditioning network and the other in rats. Stimulus generalization was unaffected in both. These findings support the validity of the model as an approach to studying the neural basis of conditioned fear learning, and in addition suggest that the thalamo-amygdala pathway, possibly by the use of population coding, is capable of performing at least crude stimulus discriminations.   相似文献   
98.
Background: Australia is a developed country, However; Aboriginal Australians have rates of blindness comparable to Third World countries. There have been well-funded eye health programs for 15 years in Central Australia. This paper examines if there has been an improvement in visual disability of one traditional group of Aboriginal Australians. Methods: Results from an eye health survey of the Anangu Pitjantjatjara of South Australia in 1990 are presented. These data are compared with results for ‘blindness’ and ‘poor vision’ from a national survey undertaken in 1976. The two surveys were comparable in design, both were cross-sectional population-based prevalence surveys. Prevalence rates were adjusted for the size of the source population. Results: Young rural Aboriginal Australians have good visual acuity. Low vision and blindness (WHO definitions) occur in 19.6% and 10.4% of 60+ year olds, respectively. Women were more likely than men to be blind or have low vision (OR= 1.93; 1.06-3.58). There was a decline in ‘poor vision’ between surveys (OR=2.86; 1.86-4.75) but not in ‘blindness’. Conclusion: Although there has been a reduction in the prevalence of visual disability in rural Aboriginal Australians, improvements in the provision of eye care for the elderly need to occur.  相似文献   
99.
A 59-year-old white woman with temporal arteritis developed progressive renal failure. Renal biopsy results showed focal and segmental necrotizing glomerulonephritis; furthermore, giant cells were present in the destructed vessel walls. Immunosuppressive therapy did not prevent terminal renal failure. This case shows that renal involvement may be a feature of temporal arteritis.  相似文献   
100.
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