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   353篇
  免费   45篇
儿科学   9篇
妇产科学   1篇
基础医学   109篇
口腔科学   2篇
临床医学   22篇
内科学   90篇
皮肤病学   37篇
神经病学   20篇
特种医学   6篇
外科学   43篇
综合类   2篇
一般理论   1篇
预防医学   22篇
眼科学   3篇
药学   15篇
肿瘤学   16篇
  2021年   10篇
  2019年   3篇
  2018年   8篇
  2017年   3篇
  2016年   5篇
  2015年   10篇
  2014年   8篇
  2013年   14篇
  2012年   20篇
  2011年   25篇
  2010年   9篇
  2009年   10篇
  2008年   23篇
  2007年   17篇
  2006年   22篇
  2005年   19篇
  2004年   19篇
  2003年   9篇
  2002年   9篇
  2001年   13篇
  2000年   17篇
  1999年   18篇
  1998年   5篇
  1997年   2篇
  1996年   2篇
  1995年   5篇
  1994年   7篇
  1993年   3篇
  1992年   8篇
  1991年   11篇
  1990年   6篇
  1989年   8篇
  1987年   2篇
  1986年   2篇
  1985年   4篇
  1984年   2篇
  1982年   5篇
  1979年   2篇
  1977年   5篇
  1976年   3篇
  1973年   1篇
  1972年   3篇
  1971年   1篇
  1970年   2篇
  1969年   2篇
  1968年   1篇
  1967年   3篇
  1965年   2篇
  1961年   1篇
  1956年   2篇
排序方式: 共有398条查询结果,搜索用时 15 毫秒
1.
This study reports on beta 2-microglobulin (beta 2M) deposits in the skin of 12 uremic patients and three kidney transplant recipients compared with eight healthy controls. Uremic patients were treated by hemodialysis (HD), hemofiltration (HF), hemodiafiltration (HDF), or continuous ambulatory peritoneal dialysis (CAPD) for a period lasting from 1 to 19 years. Congo red staining of the skin was negative in patients and controls. However, immunofluorescent staining with an anti-beta 2-microglobulin monoclonal antibody was positive in the skin of all patients and of six of the eight controls. Beta 2M skin deposition is more intense in patients than in controls and increases with patient age and the duration of dialysis. A stron correlation is observed between the extent of skin beta 2M deposits and clinical manifestations due to beta 2M deposits in internal organs. However, no correlation is found between beta 2M skin deposits and sex or beta 2M serum levels.  相似文献   
2.
3.
Hypophosphatasia is a rare inherited disorder characterized by defective bone mineralization and deficiency of serum and tissue liver/ bone/kidney tissue alkaline phosphatase (L/B/K ALP) activity. We report the characterization of tissue-nonspecific alkaline phosphatase (TNSALP) gene mutations in a series of 9 families affected by severe hypophosphatasia. Fourteen distinct mutations were found, 3 of which were previously reported in the North American or Japanese populations. Seven of the 11 new mutations were missense mutations (M45L, R119H, G145V, C184Y and H154Y, D289V, E459K), the four others were 2 single nucleotide deletions (544delG and 1172delC), a mutation affecting donor splice site (862 + 5A) and a nonsense mutation (R411X).  相似文献   
4.
Immunohistochemical study of the exo- and endocervix in squamous metaplasia is performed using EE21-06d monoclonal antibodies revealing simultaneously five cytokeratinous polypeptides characteristic of squamous epithelium, and f-12-19h revealing simultaneously wide spectrum of cytokeratinous polypeptides characteristic of the epithelium various types. PAP method and the reaction of immunofluorescence were used. Monoclonal antibodies 12-19d label cells of all layers of normal exocervix, endocervix and metaplastic squamous epithelium, both immature and differentiated. Monoclonal antibodies EE21-06d react in the exocervix with suprabasal and higher located cells and in the endocervix with reserve cells only. Positive reaction with EE21-06d in the metaplastic foci increases in proportion with the squamous cell differentiation, thus this antibody being the marker of reserve cells and the degree of the squamous metaplasia maturity.  相似文献   
5.
We studied the spontaneous in vitro secretion of anti-HIV-1 antibodies by peripheral blood mononuclear cells (PBMC) from HIV-1-infected patients. Specific antibody production was detected in supernatants of PBMC cultures using an ELISA; HIV-1 specificity was confirmed by antigen adsorption and Western blotting. This antibody secretion was found to be an active phenomenon and was not due to a release of plasma antibodies passively adsorbed onto the cell membranes. In all positive supernatants, anti-HIV-1-secreted antibodies were directed against env-encoded antigens and many supernatants also contained antibodies to pol- and gag-encoded antigens. PBMC from all HIV-1-infected patients tested (140 adults and 18 infants) secreted anti-HIV-1 antibodies. This production was found during all the clinical stages of HIV-1 infection. Our results suggest that this spontaneous HIV-1-specific antibody secretion represents a marker of HIV-1 infection. Detection of these antibodies could be a valuable tool for early confirmation of HIV-1 infection in neonates born to HIV-1-seropositive mothers.  相似文献   
6.
The nature of the aging process has been the subject of considerable speculation. Now, some data indicate that free radical reactions going on continuously in the cells contribute to aging. Considering these data, we have investigated the activity of enzymes (catalase, glutathione peroxidase, superoxidismutase) present physiologically in the cell to limit to tolerable levels, the rate of free radicals or H2O2. These enzymes activities were assayed in Paramecium tetraurelia as clonal age increased. Catalase activity increases slightly during aging of paramecia, i.e. during maturity and senescence phases (20-150 fissions). No significant changes in glutathione peroxidase and superoxidismutase is found. Catalase activity was also assayed as a function of culture conditions. As the cells begin starving and the percentage of autogamous cells increases, catalase activity decreases. After autogamy, a large increase of catalase activity occurs during the sexual immaturity phase, i.e. during the first 20 fissions. By another way, H2O2 added in the culture medium (from 0 to 15 X 10(-5)M) causes an important increase of catalase activity (from 100 U.I. to 250 U.I.). The possible role of O-.2, OH. and H2O2 in aging is discussed.  相似文献   
7.
We developed an assay to detect antibodies spontaneously secreted in vitro by peripheral blood mononuclear cells (PBMC) against Brucella spp. High levels of anti-Brucella immunoglobulin G (IgG) and/or IgM and/or IgA antibodies were detected in the cell supernatant solution of PBMC cultures for 12 patients suffering from acute or focalized brucellosis and for 5 patients recently vaccinated against brucellosis. This spontaneous in vitro antibody production disappeared 5 to 20 months after onset of clinical signs and 20 to 27 days after vaccination. The transient character of this anti-Brucella antibody production by PBMC is consistent with a temporary in vivo stimulation of the immune system by Brucella antigens. Detection of this secretion could improve the diagnosis of evolutive brucellosis.  相似文献   
8.
9.
BACKGROUND: The potential of hyperechogenic fetal bowel to act as a hallmark for prenatal cystic fibrosis screening in the general population is controversial. METHODS: Our goal was to evaluate the incidence of cystic fibrosis in 209 fetuses with hyperechogenic bowel diagnosed at routine ultrasonography and with no family history of cystic fibrosis. The diagnosis of cystic fibrosis was based on prenatal screening for the eight mutations most frequently observed in France (deltaF508, deltaI507, 1717-1G-->A, G542X, G551D, R553X, W1282X, N1303K) and at postnatal follow up. RESULTS: The overall incidence of cystic fibrosis was 7/209 (3.3%) which is 84 times the estimated risk of CF in the general population (112500). Of these seven cases, six were diagnosed prenatally based on DNA analysis (deltaF508/deltaF508, n=5; deltaF508/G542X, n=1). One case in which only one mutation had been recognised was diagnosed clinically after birth (deltaF508/unidentified mutation). Of the seven cases, none was diagnosed at 16-19 weeks, four at 16-24 weeks, and three after this. The incidence of heterozygous fetuses (15/209, 7%) was not significantly higher than the 5% expected in the general population. The mutations involved in these heterozygous cases were deltaF508 (n=13), G542X (n=1), and G551D (n=1). CONCLUSIONS: Screening for cystic fibrosis should be offered to families in which fetal hyperechogenic bowel is diagnosed at routine ultrasonography. This underlines the need to review genetic counselling in this situation where the fetus is the index case for a genetic disease.  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