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   915386篇
  免费   57770篇
  国内免费   1437篇
耳鼻咽喉   12179篇
儿科学   30271篇
妇产科学   23822篇
基础医学   142487篇
口腔科学   26034篇
临床医学   80629篇
内科学   171277篇
皮肤病学   21277篇
神经病学   65138篇
特种医学   32930篇
外国民族医学   109篇
外科学   135932篇
综合类   17890篇
现状与发展   2篇
一般理论   200篇
预防医学   67658篇
眼科学   21428篇
药学   69994篇
  14篇
中国医学   2547篇
肿瘤学   52775篇
  2018年   9672篇
  2017年   7305篇
  2016年   8205篇
  2015年   8965篇
  2014年   12369篇
  2013年   18708篇
  2012年   25120篇
  2011年   26767篇
  2010年   15753篇
  2009年   14739篇
  2008年   25070篇
  2007年   27076篇
  2006年   27490篇
  2005年   25808篇
  2004年   25267篇
  2003年   24209篇
  2002年   23672篇
  2001年   45045篇
  2000年   46289篇
  1999年   38135篇
  1998年   10016篇
  1997年   8539篇
  1996年   9014篇
  1995年   8431篇
  1994年   7833篇
  1993年   7352篇
  1992年   29091篇
  1991年   29066篇
  1990年   28654篇
  1989年   28058篇
  1988年   25508篇
  1987年   24961篇
  1986年   23808篇
  1985年   22382篇
  1984年   16440篇
  1983年   14105篇
  1982年   7886篇
  1979年   15500篇
  1978年   11110篇
  1977年   9327篇
  1976年   8971篇
  1975年   10000篇
  1974年   11924篇
  1973年   11460篇
  1972年   10859篇
  1971年   10284篇
  1970年   9766篇
  1969年   9116篇
  1968年   8546篇
  1967年   7574篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Purpose

Intermittent hypoxia training/treatment (IHT) is an emerging therapeutic approach to alleviate chronic diseases, such as diabetes. The present study investigated the effects of IHT on blood leucocyte pyruvate dehydrogenase kinase 1 (PDK-1) mRNA expression and its relationship with the changes in blood insulin level.

Methods

Seven adult healthy volunteers and 11 prediabetic patients participated in this study. A 3-week course of IHT consisted of a 40-min session of 4 cycles of 5-min 12% O2 and 5-min room air breathing per day, 3 sessions per week for 3 weeks (i.e., total 9 sessions of IHT). Plasma insulin levels and leukocyte PDK-1 mRNA expression were determined at various time points either under fasting condition or following oral glucose tolerance test (OGTT). Correlation between the IHT-induced changes in PDK-1 mRNA and insulin or glucose levels in the same serological samples was analyzed.

Results

At pre-IHT baseline, PDK-1 mRNA expression was two times higher in prediabetes than control subjects. IHT resulted in significant augmentation in PDK-1 mRNA expression (> twofold) in prediabetes at the end of 3-week IHT and remained elevated 1 month after IHT, which was correlated with a significantly reduced insulin release and lower blood glucose after glucose loading with OGTT.

Conclusion

IHT can trigger beneficial effects in normalizing blood insulin levels in prediabetic patients under oral glucose load, which were closely correlated with an enhanced mRNA expression of PDK-1 in leukocytes. Further clinical trials are warranted to validate the utility of IHT as a non-invasive complementary therapy against diabetes-associated pathologies.

  相似文献   
102.
The bacterial cell wall provides structural integrity to the cell and protects the cell from internal pressure and the external environment. During the course of the twelve-year funding period of the Collaborative Research Center 766, our work has focused on conducting structure-function studies of enzymes that modify (synthesize or cleave) cell wall components of a range of bacteria including Staphylococcus aureus, Staphylococcus epidermidis, and Nostoc punctiforme. Several of our structures represent promising targets for interference. In this review, we highlight a recent structure-function analysis of an enzyme complex that is responsible for the amidation of Lipid II, a peptidoglycan precursor, in S. aureus.  相似文献   
103.
104.
AimTo investigate clinico-pathological features of lymphoma of the lips, and review the literature.Materials and MethodsRetrospective analysis and review of English literature, 1996-2016.ResultsAnalysis included 23 cases, 7 new cases and 16 from literature, 12 M: 11 F, age 7–82 years. Four occurred in children, mean age 10.1; 19 in adults, mean 61.1 years.The lower lip was involved in the majority of cases (16, 69.56%). 14 (60.87%) were isolated to the lips, 8 (34.78%) were multifocal. Nine (39.13%) occurred in association with Sjogren's syndrome, of which one also had Hashimoto thyroiditis. IgG4-related disease and HIV were reported in one case each. The lip salivary glands were involved in most cases (19, 82.6%); 3 (13.6%) showed only cutaneous involvement.The typical presentation was single or multiple nodules (15, 65.21%), with surface ulceration in only two (8.69%). Constituent symptoms were absent in all cases, paresthesia was reported in one (4.34%). The majority (18, 78.26%) was extranodal marginal zone B-cell lymphoma - mucosa-associated lymphoid tissue lymphoma (EMZB-MALT), and one case each was mantle cell, NK-T cell, CD30 positive and plasmablastic lymphoma.ConclusionThe lips seem to have a unique pattern of non-Hodgkin lymphoma dominated by EMZB-MALT lymphoma, rarely other types. In more than half, neither Sjogren's syndrome nor other chronic inflammation was identified. Lesions tend to present as asymptomatic slowly progressing, non-ulcerated submucosal masses. Lymphoma should be considered even in the absence of constituent symptoms, as most cases showed none. Although the number of reported cases is rather small, disease course is usually prolonged and prognosis seems to be good.  相似文献   
105.
106.
107.
The measures for leishmaniasis control include the precise diagnosis of disease. However, although several recombinant antigens have been tested with this biotechnological purpose, no effective product exists, which could detects patients with the active disease, as well as differentiates them from cured and treated patients. In this study, a conserved Leishmania hypothetical protein, which was identified in Leishmania infantum parasites, but evaluated to presents high homology in the amino acid sequences between distinct parasite species, was evaluated for the diagnosis of tegumentary and visceral leishmaniasis. In addition, PBMCs collected from treated and untreated mucosal leishmaniasis (ML) and visceral leishmaniasis (VL) patients, as well as in healthy subjects living in endemic region of disease, were in vitro stimulated, when IFN-γ, IL-4 and IL-10 levels were evaluated in the cell supernatant. Regarding the serological analyses, ELISA experiments using the recombinant protein (rLiHyL) and a human serological panel revealed high sensitivity and specificity values to detect both diseases, while control antigens showed worst results. Regarding the cellular response, results showed that rLiHyL-stimulated cells produced higher IFN-γ and lower IL-4 and IL-10 levels in the supernatants. Also, the anti-protein antibody production was evaluated in these patients, and data showed higher IgG2 and lower IgG1 levels found in the treated patients and healthy controls, demonstrating the stimulation of a Th1-type response induced by the rLiHyL protein. In conclusion, this hypothetical protein can be considered as antigenic in TL and VL, as well as a vaccine candidate to be tested in future studies to protect against disease.  相似文献   
108.
Neuroscience and Behavioral Physiology - We report here a comparative (using chemical, electrical, and optical stimulation) study of the electrophysiological properties of cultured hippocampal...  相似文献   
109.
Neuroscience and Behavioral Physiology - Widening and deepening our understanding of how the brain works requires constant improvements not only in methods of recording neuron activity, but also...  相似文献   
110.
Neuroscience and Behavioral Physiology - We report here a comparative analysis of the acute antidepressant actions of derivatives of 3-hydroxypyridine and succinic acid (emoxypine, Reamberin, and...  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