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   8016篇
  免费   1篇
耳鼻咽喉   259篇
儿科学   1篇
妇产科学   132篇
基础医学   962篇
口腔科学   253篇
临床医学   1536篇
内科学   788篇
神经病学   97篇
特种医学   381篇
外科学   1925篇
综合类   2篇
预防医学   581篇
眼科学   151篇
药学   283篇
中国医学   1篇
肿瘤学   665篇
  2018年   1篇
  2016年   2篇
  2013年   1篇
  2012年   314篇
  2011年   664篇
  2010年   310篇
  2009年   1篇
  2008年   466篇
  2007年   668篇
  2006年   684篇
  2005年   676篇
  2004年   798篇
  2003年   796篇
  2002年   860篇
  2001年   534篇
  2000年   729篇
  1999年   370篇
  1998年   108篇
  1997年   1篇
  1993年   23篇
  1991年   4篇
  1988年   1篇
  1987年   1篇
  1984年   1篇
  1976年   1篇
  1972年   3篇
排序方式: 共有8017条查询结果,搜索用时 296 毫秒
21.
Gene P504S is considered as the most specific for prostatic carcinoma and its protein (alpha-methylacyl coenzyme A racemaze (AMACR/P504S) is higly sensitive and specific marker not only for adenocarcinoma cells but also for preceding changes - prostatic intraepithelial neoplasm (PIN). AMACR/P504S seems to be the first marker of malignant transformation and tumor progression. Use of immunohistochemical method for revealing this marker together with methods of basal prostatic cells observation (cytokeratin of a high molecular weight, cytokeratin 5/6, p63) improves morphological diagnosis of prostatic carcinoma, particularly on the material of needle biopsies. This combination allows one to identify neoplastic nature of some difficult lesions.  相似文献   
22.
Histological, histochemical and immunohistochemical studies of 50 solitary juvenile polyps (JP) and 50 JP from children with juvenile polyposis syndrome (JPS) were performed. Observations of the focal complex glandular structures with high mitotic rate were more frequent in JP from patients with JPS (n = 29, 58%) than in solitary JP (n = 17, 34%) (p < 0.03). The immunohistochemical study demonstrated p53 overexpression in individual cells and more than 50% of Ki-67-positive cells in 5 (10%) solitary JP and in 17(34%) JP from patients with JPS (p < 0.007). The finding of microglandular pattern is more typical for JP from patients with JPS. Pathological data, expression of p53 and Ki-67 by immunohistochemistry could help to pick out the group of JP with dysplastic changes.  相似文献   
23.
24.
Phylogenetic analysis of nucleotide sequences of gag and env genes of type 1 human immunodeficiency virus (HIV-1) variants isolated from individuals infected through sexual intercourse or nosocomially (by injections with nonsterile syringes) showed that 5 of 27 (18.5%) isolated strains were recombinants. Two viruses found in the Russian Far East had gagAenvE genotype, three other recombinants had envG genotype; gag gene of one isolate belonged to subtype A and gag genes of two others belonged to subtype D. Detection of new recombinant variants in addition to the A/B recombinant described previously shows that these viruses can contribute to the HIV-1 genetic variability in Russia.  相似文献   
25.
26.
The lamellar bone mineral component in mature and senile age was studied using the methods of transmission electron microscopy and cryofractography. This component was shown to be formed by crystals (13-4 x 7-8 x 3-4 nm) of the prismatic shape that formed coplanar units (29-3 x 18-21 x 3-4 nm). The peculiarities of mineral particle distribution inside and between the collagen fibrils, as well as on the completely formed areas of bone surface, were detected. It was established that the length and the width of coplanar crystal aggregates was significantly higher in senile age as compared to similar linear parameters defined in persons of mature age (by 17-20 and 5-9%, respectively).  相似文献   
27.
The paper summarizes the results of 25-year study of Legionnaires' disease (Legionnaire's bacillus infection) in its epidemiology, diagnosis, and prevention, the taxonomy and biology of the causative organism. Emphasis is laid on the contribution of the Russian school of investigators in studying this problem. Despite the intensive efforts in investigating the infection and its causative organism, there are still many problems in predicting and preventing the epidemics of Legionnaires' disease, which annually occur in different countries of the world. Legionnaires' disease is a typical example of technogenic infections: active industrial and domestic uses of closed water circulating systems in industry and aerosol sources promote the spread of the infection caused by Legionnaire's bacillus and make its control in these systems. Despite the introduction of current immunological and molecular genetic methods, diagnosis is effective only for L. pneumophila, serogroup 1. The sensitivity and specificity of methods for diagnosis and identification for other 15 L. pneumophila serogroups and 41 species of L. bacilli are far from being perfect. L. bacilli are also a most popular object for studying the biochemical and genetic aspects of its intracellular parasitism.  相似文献   
28.
The aim of this work was to demonstrate the role of interferon alpha (IA) in apoptosis control of cells of hypothalamohypophysial adrenocortical system (HHAS) in young and old mice under conditions of hyperoxia. The increase of functional activity of neurosecretory cells of hypothalamic paraventricular nucleus in old mice treated with IA was demonstrated, while no effect was found in young mice. This differences could be associated with aging changes in HHAS in intact old animals. Oxidative stress caused an increase in the number of cells synthesizing proapoptotic c-fos protein in paraventricular nucleus of mice of both age groups. However, the protective action of IA against the stress is expressed more actively and in more early stage of apoptosis in young mice. Thus, the degree of IA participation in the control of programmed cell death of hypothalamic cells depends on the age of the animal. In the adrenal zona fasciculata of young mice the number of apoptotic cells was significantly increased after IA administration while after hyperoxia or its combination with IA it remained at control level. In the adrenal gland of old mice the proportion of apoptotic cells was not different from that found in young mice and remained unchanged after all experimental challenges.  相似文献   
29.
The review examines the current data on the cellular and tissue mechanisms of scar formation in the liver. On the basis of the analysis of the literature, authors conclude that to minimize the destructive processes in the liver, the most advisable and promising method during the operations on this organ is the use of laser surgical devices. However, the problems of the selection of the optimal regimes of laser radiation and of the methods of conducting these operations to promote reliable and rapid healing of postoperative wound of the liver.  相似文献   
30.
76 endometrioid adenocarcinomas of the uterine body were studied. Expression of the above markers is of essential value together with metastatic involvement of regional lymph nodes, stage of the disease and pathogenetic variant for determining prognosis of carcinoma aggressiveness and disease outcome. Positive hormonal-receptor status of the tumor is characterized by well-differentiated tumor cells, small depth of invasion, rare metastases to regional lymph nodes and higher survival (5 year--81%) of patients comparing with cases where ER and PR were not determined (53%). On the contrary, overexpression of oncoprotein HER-2 and Ki-67 higher than median (42%) was associated with high tumor aggression resulting finally in a significant fall in the survival (from 75% to 58% and from 79% to 60%, respectively). Combination of HER-2 overexpression with a high level of Ki-67 is particularly unfavourable (5-year survival--43%).  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