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   335篇
  免费   12篇
  国内免费   7篇
耳鼻咽喉   3篇
儿科学   8篇
妇产科学   6篇
基础医学   50篇
口腔科学   7篇
临床医学   18篇
内科学   51篇
神经病学   56篇
特种医学   12篇
外科学   50篇
综合类   3篇
预防医学   7篇
眼科学   2篇
药学   71篇
肿瘤学   10篇
  2023年   1篇
  2022年   4篇
  2021年   16篇
  2020年   5篇
  2019年   6篇
  2018年   12篇
  2017年   7篇
  2016年   7篇
  2015年   7篇
  2014年   16篇
  2013年   14篇
  2012年   29篇
  2011年   37篇
  2010年   15篇
  2009年   15篇
  2008年   20篇
  2007年   11篇
  2006年   14篇
  2005年   11篇
  2004年   10篇
  2003年   8篇
  2002年   8篇
  2001年   3篇
  2000年   3篇
  1999年   2篇
  1998年   2篇
  1997年   2篇
  1995年   4篇
  1994年   1篇
  1993年   3篇
  1992年   4篇
  1991年   2篇
  1990年   6篇
  1989年   9篇
  1988年   8篇
  1987年   7篇
  1986年   7篇
  1985年   6篇
  1984年   5篇
  1983年   2篇
  1982年   1篇
  1981年   1篇
  1973年   1篇
  1968年   2篇
排序方式: 共有354条查询结果,搜索用时 15 毫秒
1.
Eight healthy volunteers received 50 mg of dimenhydrinate, a theoclate salt of diphenhydramine, orally, sublingually, and intravenously on three separate occasions in random sequence. Plasma diphenhydramine concentrations during 12 h after each dose were measured by gas-liquid chromatography with nitrogen-phosphorous detection. Mean peak plasma concentrations after sublingual administration were slightly lower than after oral dosage (38.3 vs 47.8 ng ml-1), and the time of peak concentration was similar (2.6 vs 2.3 h after dose). These differences did not reach statistical significance. The mean total area under the plasma concentration-time curve (AUC) for sublingual administration was slightly but not significantly smaller than after oral dosage (221 vs 270 h ng ml-1). Systemic availability of diphenhydramine after sublingual dimenhydrinate, measured by the ratio of oral AUC to intravenous AUC, was slightly less than after oral dimenhydrinate (0.58 vs 0.69, NS), and both were significantly less than 1.0. Thus sublingual and oral administration of dimenhydrinate result in comparable, but incomplete, systemic availability of diphenhydramine.  相似文献   
2.
3.
The present work demonstrated that nitric oxide (NO) modulates Na+, K+-ATPase activity in the proximal rat trachea. Sodium nitroprusside induced concentration-dependent (10-100 microM) stimulation in proximal trachea Na+, K+-ATPase activity. The effect was specific for Na+, K+-ATPase since Mg-ATPase activity was unaffected. This NO-donor changed neither Na+, K+-ATPase nor Mg-ATPase activity in the distal segment. The modulatory action on Na+, K+-ATPase induced by sodium nitroprusside was linked to an increase in nitrates/nitrites and cyclic GMP levels in proximal segments. Modulation of proximal Na+, K+-ATPase activity by sodium nitroprusside was mimicked by S-nitroso-N-acetylpenicillamine (100 microM) and 8-bromo-cyclic GMP (100 microM). Both sodium nitroprusside and 8-bromo-cyclic GMP effects on Na+, K+-ATPase activity of proximal segments of trachea were blocked by 2 microM of KT 5823 (a cyclic GMP-dependent protein kinase inhibitor), but not by 0.5 microM of KT 5720 (a cyclic AMP-dependent protein kinase inhibitor). Both kinase inhibitors decreased proximal Na+, K+-ATPase activity, but did not change Mg-ATPase activity. Okadaic acid (1 microM), a phosphatase-1 inhibitor, increased proximal Na+, K+-ATPase but not Mg-ATPase activity. The effect of okadaic acid was non-additive with that of 8-bromo-cGMP on Na+, K+-ATPase activity. Our results suggest that NO modulates proximal rat trachea Na+, K+-ATPase activity through cyclic GMP and cyclic GMP-dependent protein kinase.  相似文献   
4.
Background: The presence in bone marrow of cells which react with monoclonal antibodies against tumor-associated antigens has been proposed over the last few years as a new prognostic factor in breast cancer patients. Patients and methods: Bone marrow aspirates were obtained from 109 stage I and II breast cancer patients during or 2–4 weeks after primary surgery. The samples were processed for leukocyte separation on a Ficoll-Hypaque gradient and then used to prepare cytospin slides for immunocytochemical analysis. The slides were stained with a pool of monoclonal antibodies (MoAbs) which recognize tumor associated antigens, using the alkaline phosphatase anti-alkaline phosphatase method. The median follow-up was 36 months (range 15–62); 22 patients relapsed and 7 died. Results: Thirty-four of the 109 patients (31.1%) had MoAb positive bone marrow cells. The bone marrow was positive in 28/74 (37.9%) patients who had the aspirate taken during surgery and in 6/35 (17.1%) who had it taken after surgery (p = 0.055). No association was found between bone marrow positivity and tumour size, nodal status, menopausal status, estrogen receptor positivity or the proliferative index. No association was found between bone marrow and prognosis: the log-rank test was 0.291 (p > 0.5) for OS and 0.023 for DFS; the hazard ratio (positive vs negative) was 1.51 for OS (95% CI: 0.33–6.86) and 0.93 for DFS (95% CI: 0.35–2.45). Conclusions: In our series, bone marrow positivity did not correlate with prognostic parameters or prognosis. Of interest is the relative excess of positivity when the bone marrow was obtained during surgery.  相似文献   
5.
6.
BACKGROUND: Electrophysiologically, ventricular fibrillation is defined as a "chaotic, random, asynchronous electrical activity of the ventricles due to repetitive re-entrant excitation and/or rapid focal discharge". To this point its morphological equivalent has not been defined. MATERIAL AND METHOD: Several groups of different diseases and types of accidental death in normal subjects were studied. A complete autopsy was performed and the hearts were examined in 432 cases. A total of 16 myocardial samples per heart were processed for histological examination and sections were stained by haematoxylin and eosin or by specific stains. The frequency, location and extent of myocellular segmentation (stretching and/or rupture) of intercalated discs and associated changes of myocardial bundles and single myocells were investigated. A quantitative analysis was performed and the data were processed for statistical evaluation. RESULTS: The frequency of MFB was maximal in coronary (88%) and Chagas (76%) groups followed by the intracranial brain haemorrhage group (52%). The extent of myofiberbreak-up was maximal in coronary/Chagas groups followed by intracranial haemorrhage and transplant groups. CONCLUSIONS: No correlation was seen between gender, age, heart weight, degree of coronary atherosclerosis, myocardial fibrosis, survival and MFB. If our postulate is correct, finding MFB in the myocardium might allow the diagnosis of a malignant arrhythmia followed by cardiac arrest due to ventricular fibrillation even in the absence of clinical information (sudden death out-of-hospital).  相似文献   
7.
Inflammation Research - Allergic rhinitis (AR) is characterized by typical symptoms that are dependent on inflammation. Poly-allergy is a frequent phenomenon. Phenotyping AR represents an...  相似文献   
8.
9.
The nontyphoidal Salmonella enterica serovar Dublin is adapted to cattle but infrequently infects humans, very often resulting in invasive infections with high levels of morbidity and mortality. A Salmonella-induced intestinal acute inflammatory response is postulated as a mechanism to prevent bacterial dissemination to systemic sites. In S. enterica serovar Typhimurium, flagella contribute to this response by providing motility and FliC-mediated activation of pattern recognition receptors. In this study, we found 4 Salmonella enterica isolates, with the antigenic formula 9,12:−:−, that, based on fliC sequence and multilocus sequence type (MLST) analyses, are aflagellate S. Dublin isolates. Interestingly, all were obtained from human bloodstream infections. Thus, we investigated the potential role of flagella in the unusual invasiveness exhibited by S. Dublin in humans by analyzing flagellation and proinflammatory properties of a collection of 10 S. Dublin human clinical isolates. We found that 4 of 7 blood isolates were aflagellate due to significantly reduced levels of fliC expression, whereas all 3 isolates from other sources were flagellated. Lack of flagella correlated with a reduced ability of triggering interleukin-8 (IL-8) and CCL20 chemokine expression in human intestinal Caco-2 cells and with reduced early inflammation in the ceca of streptomycin-pretreated C57/BL6 mice. These results indicate that flagella contribute to the host intestinal inflammatory response to Salmonella serovar Dublin and suggest that their absence may contribute to its systemic dissemination through dampening of the gut immune response. Analysis of FliC production in a collection of cattle isolates indicated that the aflagellate phenotype is widely distributed in field isolates of S. Dublin.  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