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   303篇
  免费   16篇
  国内免费   1篇
  320篇
  2022年   4篇
  2021年   2篇
  2020年   4篇
  2019年   2篇
  2018年   3篇
  2017年   6篇
  2016年   8篇
  2015年   9篇
  2014年   9篇
  2013年   24篇
  2012年   30篇
  2011年   28篇
  2010年   20篇
  2009年   13篇
  2008年   22篇
  2007年   24篇
  2006年   24篇
  2005年   12篇
  2004年   19篇
  2003年   16篇
  2002年   11篇
  2001年   2篇
  1999年   2篇
  1998年   6篇
  1997年   2篇
  1996年   2篇
  1995年   2篇
  1994年   2篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   1篇
  1981年   1篇
  1975年   1篇
  1963年   1篇
排序方式: 共有320条查询结果,搜索用时 15 毫秒
291.
The aim of this retrospective study was to create guidelines for therapy of severe sepsis in surgical intensive care unit (ICU) for unknown causative agent based on antimicrobial susceptibility of causative bacteria. Seventy-four patients with severe sepsis from surgical ICU in 2003.-2005. were included in study. Their clinical and microbiological data were analyzed from the medical records. Antimicrobial susceptibility of the strains isolated from the blood-culture was tested by disk diffusion method according to CLSI (Clinical Laboratory Standard Institution). APACHE II score was used to predict the severity of illness. Statistical significance difference between results was tested by Mann-Whitney test and chi2 test. Important problem remained type of sepsis: mono-agent sepsis presented less therapeutic problem than sepsis caused with two or more agents (mixed sepsis). Methicillin-resistant Staphylococcus aureus (MRSA), Pseudomonas aeruginosa and Acinetobacter baumannii were predominant causative agents in both type of sepsis. There was remarkable increase of A. baumannii prevalence in 2005 compared to 2004 and to 2003. There was also decrease of MRSA prevalence in 2004 and 2005 compared to 2003. P. aeruginosa were the predominant causative agents in 2004. MRSA displayed good susceptibility to vancomycin and linezolide, whereas P. aeruginosa showed excellent susceptibility to ceftazidime and carbapenems. A. baumannii, third predominant causative agent, exhibited excellent susceptibility to ampicillin+ sulbactam and carbapenems. The recommended therapy is empirical and should cover all important pathogens.  相似文献   
292.
The impact of L-arginine (LA), a precursor for synthesis of nitric oxide (NO), and N-omega-nitro-L-arginine methyl ester (L-NAME, LN), a non-selective inhibitor of the enzyme producing nitric oxide (nitric oxide synthase; NOS) chronic toxicity induced lesions on Ascites - Pulmonary hypertension syndrome (PHS) development was investigated in 140 one-day-old male broiler chickens (ROSS) during the first 5 weeks of life. Every second day the animals were treated intraperitoneally (ip) with L-NAME (10 mg/kg of body weight; BW), L-arginine (100 mg/kg BW), L-arginine and L-NAME in combination (100 mg/kg BW and 10 mg/kg BW respectively), and with physiological saline (0.90% w/v of NaCl; 0.5 mL/kg BW). Seven birds from each group were euthanized every week. The histopathological examination of the heart, the liver, the lungs, the blood vessels and the lymphoid organs, was performed. Also the organ index values were determined. At the end of the experiment the pre-ascitic condition or ascites - PHS was confirmed in five dead animals in the L-NAME-treated group. In the same group the edema was the most prominent histopathological change confirmed in the heart and in the lungs of the sacrificed chickens. In L-arginine-treated group the congestion and the haemorrhages were the striking changes in the same organs with the highest degree in the last two weeks of trial. While the focal disruption of myocardiofibriole and hepatocytes were predominant lesions in L-NAME-treated chickens (5th and 4th weeks, respectively), in L-NAME/L-arginine-treated group only the mild focal myocardial degeneration was seen. According to the most of the results of present investigation, it was concluded that the consecutive treatment with L-NAME provoked ascites - PHS, while L-arginine has protective effect in this animal model of disease.  相似文献   
293.
The encapsulation of different immunomodulating peptides, the peptidoglycan monomer, its semisynthetic derivatives (Adamant-1-yl)-acetyl-peptidoglycan monomer and Boc-Tyr-peptidoglycan monomer, respectively, and of two diastereoisomers of adamantyltripeptides into the large negatively charged multilamellar liposomes was investigated. The reproducible quantitative method using HPLC was established for the determination of the entrapped compounds. It was shown that the tested compounds could be efficiently incorporated into liposomes using either the film or modified film method. The results confirmed that the peptidoglycans with lipophilic substituents and particularly the adamantyltripeptides were incorporated into liposomes with higher efficiency than the peptidoglycan monomer using either of the described methods. Liposome preparations were stable at 4 degrees C up to seven days as shown by minimal leaking of the entrapped material.  相似文献   
294.
The hypothesis was tested that a specific pattern in the cysteine cathepsin/inhibitor ratio is associated with the development of more aggressive tumor cell phenotypes in squamous cell carcinoma of the head and neck (SCCHN). For this purpose commercially available ELISAs were used to determine the concentrations of cysteine cathepsins B and L and their inhibitors, stefins A and B, in cytosols of nontumorous mucosa and primary tumors from 92 patients. Using the stefin A concentration difference in matched pairs of tissue samples as a stratifying variable, 53 cases were found to be upregulated (higher concentrations in tumor samples than in nontumorous mucosa) and 39 cases downregulated. Disease recurrence was more frequent in the downregulated group than in the upregulated group (35.9% vs 11.3%, p=0.009), which resulted in significantly different 5-year disease-free survival rates (61.2% vs 88%, p=0.004). The consistency of these results was confirmed by repeating the analysis in an independent group of patients (the reference group). The presented results suggest that in patients with SCCHN, specific patterns in the proteolytic profile of cysteine proteases and their inhibitors are associated with the development of distinctly aggressive tumor cell phenotypes and are of prognostic value.  相似文献   
295.
296.
297.
The 16S rRNA methyltransferase Sgm from "Micromonospora zionensis" confers resistance to aminoglycoside antibiotics by specific modification of the 30S ribosomal A site. Sgm is a member of the FmrO family, distant relatives of the S-adenosyl-L-methionine (SAM)-dependent RNA subfamily of methyltransferase enzymes. Using amino acid conservation across the FmrO family, seven putative key amino acids were selected for mutation to assess their role in forming the SAM cofactor binding pocket or in methyl group transfer. Each mutated residue was found to be essential for Sgm function, as no modified protein could effectively support bacterial growth in liquid media containing gentamicin or methylate 30S subunits in vitro. Using isothermal titration calorimetry, Sgm was found to bind SAM with a K(D) (binding constant) of 17.6 microM, and comparable values were obtained for one functional mutant (N179A) and four proteins modified at amino acids predicted to be involved in catalysis in methyl group transfer. In contrast, none of the G135, D156, or D182 Sgm mutants bound the cofactor, confirming their role in creating the SAM binding pocket. These results represent the first functional characterization of any FmrO methyltransferase and may provide a basis for a further structure-function analysis of these aminoglycoside resistance determinants.  相似文献   
298.
Keloids are benign tumors that usually develop as an excessive healing response to injury. They remain a challenging therapeutic problem to this day. Numerous treatment approaches are available, yet therapeutic results are often not satisfactory. A female patient with multiple spontaneously developed keloids on her trunk is presented. In this patient, four different therapeutic options were employed at different sites, with variable responses. The first option included cryotherapy, with poor effect. Slight flattening was observed after intralesional corticosteroid therapy. Treatment with excision followed by radiotherapy resulted in recurrence after 3 months. The best effect was noticed when excision and injection of corticosteroids into surgical margins were followed by radiotherapy. To the authors' knowledge, this is the first report of three-modal therapy in the management of keloids, which resulted in no recurrences over a 3-year follow-up.  相似文献   
299.
This study was performed to assess the effect of the S447X and Hind III lipoprotein lipase gene polymorphisms on development of coronary artery disease and hypertriglyceridemia. The study included 132 patients and 98 healthy control subjects of Croatian descent. The lipoprotein lipase S447X polymorphism was associated with coronary artery disease and hypertriglyceridemia, as indicated by the lower frequency of S447 allele in the patient group (p = 0.005) and odds ratio (O.R = 0.40, p = 0.006). The patient and control groups also showed a significant difference in the distribution of Hind III/S447X genotype combinations (p = 0.013). There were no significant associations with lipid parameters for any genotype or genotype combination in the patient group. Frequencies of the S447X polymorphism and S447X/Hind III combinations differed between the CAD/TG and control group, thus these polymorphisms may be associated with CAD and hypertriglyceridemia.  相似文献   
300.
Grifola frondosa strain GF3, was cultivated on solid-state substrate consisting of milled whole corn plant (Zea mays) and olive press cake supplemented with mineral additives and olive oil. Maintenance of the moisture content in the solid substrate is of crucial importance. Moistures higher than 70% promote growth of G. frondosa mycelium and polysaccharide production. Four fractions of pure extracellular beta-D-glucans with total mass 127.2mg and four fractions of intracellular polysaccharides with total mass 47.2mg were isolated. Polysaccharides were further separated by ion-exchange, gel and affinity chromatography. Isolated polysaccharide fractions from fungal mycelium proved to induce moderate amounts of TNF-alpha in PBMC cells in vitro. The extent of TNF-alpha induction was up to 322pgmL(-1) at a polysaccharide concentration of 200microgmL(-1) for the intracellular fraction. The TNF-alpha inducing activity is comparable to romurtide, which has been used as a supporting therapy in cancer patients treated with radiotherapy and/or chemotherapy.  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