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   176篇
  免费   8篇
  184篇
  2024年   3篇
  2023年   1篇
  2022年   4篇
  2021年   6篇
  2019年   6篇
  2018年   11篇
  2017年   4篇
  2016年   5篇
  2015年   9篇
  2014年   14篇
  2013年   9篇
  2012年   13篇
  2011年   11篇
  2010年   1篇
  2009年   7篇
  2008年   7篇
  2007年   9篇
  2006年   10篇
  2005年   7篇
  2004年   6篇
  2003年   2篇
  2002年   3篇
  2001年   3篇
  2000年   3篇
  1999年   3篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1993年   1篇
  1992年   1篇
  1990年   2篇
  1989年   3篇
  1988年   1篇
  1987年   2篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1980年   2篇
  1979年   3篇
  1978年   2篇
  1975年   2篇
  1973年   1篇
排序方式: 共有184条查询结果,搜索用时 0 毫秒
81.
Biosorption of silver ions by processed Aspergillus niger biomass   总被引:1,自引:0,他引:1  
Summary An alkali treated A. niger biomass was found to efficiently sequester silver ions from dilute as well as concentrated solutions (2.5–1000 ppm Ag+), with an ability to bind it to a level of upto 10% of dry weight. Biosorption of silver ions was not influenced by pH between 5–7. The bound Ag+ could be fully desorbed by dilute HNO3 and the biosorbent regenerated by washing with Ca2+/Mg2+ solution. This biosorbent is unique in that the mechanism of metal ion sorption has been found to be exclusively by stoichiometric exchange with Ca2+ and Mg2+ of the biosorbent.  相似文献   
82.
Elevated levels of insecticides detoxifying enzymes, such as esterases, glutathione S‐transferases (GSTs), and cytochrome P‐450 monooxygenases, act in the resistance mechanisms in insects. In the present study, levels of these enzymes in the insecticide‐resistant ground spider Pardosa sumatrana (Thorell, 1890) were compared with a susceptible population (control) of the same species. Standard protocols were used for biochemical estimation of enzymes. The results showed significantly higher levels of nonspecific esterases and monooxygenases in resistant spiders compared to controls. The activity of GSTs was lower in the resistant spiders. Elevated levels of nonspecific esterases and monooxygenases suggest their role in metabolic resistance in P. sumatrana. The reduced levels of total protein contents revealed its possible consumption to meet energy demands.  相似文献   
83.
84.

Background

Rabies is a uniformly fatal disease, but preventable by timely and correct use of post exposure prophylaxis (PEP). Unfortunately, many health care facilities in Pakistan do not carry modern life-saving vaccines and rabies immunoglobulin (RIG), assuming them to be prohibitively expensive and unsafe. Consequently, Emergency Department (ED) health care professionals remain untrained in its application and refer patients out to other hospitals. The conventional Essen regimen requires five vials of cell culture vaccine (CCV) per patient, whereas Thai Red Cross intradermal (TRC-id) regimen requires only one vial per patient, and gives equal seroconversion as compared with Essen regimen.

Methodology/Principal Findings

This study documents the cost savings in using the Thai Red Cross intradermal regimen with cell culture vaccine instead of the customary 5-dose Essen intramuscular regimen for eligible bite victims. All patients presenting to the Indus Hospital ED between July 2013 to June 2014 with animal bites received WHO recommended PEP. WHO Category 2 bites received intradermal vaccine alone, while Category 3 victims received vaccine plus wound infiltration with Equine RIG. Patients were counseled, and subsequent doses of the vaccine administered on days 3, 7 and 28. Throughput of cases, consumption utilization of vaccine and ERIG and the cost per patient were recorded.

Conclusions/Significance

Government hospitals in Pakistan are generally underfinanced and cannot afford treatment of the enormous burden of dog bite victims. Hence, patients are either not treated at all, or asked to purchase their own vaccine, which most cannot afford, resulting in neglect and high incidence of rabies deaths. TRC-id regimen reduced the cost of vaccine to 1/5th of Essen regimen and is strongly recommended for institutions with large throughput. Training ED staff would save lives through a safe, effective and affordable technique.  相似文献   
85.
Genetic and epigenetic anomalies accountable for genetic dysregulation are the most common aberrations that determine the underlying heterogeneity of the tumor cells. Currently, phosphatase and tensin homolog (PTEN) incongruity has emerged as potent and persuasive malfunctioning in varied human malignancies. In this study, we have analysed the promoter hypermethylation and expression status of PTEN. We identified different mutations in the exonic region of PTEN. Functional consequences of these mutations were explored using in silico techniques. Promoter hypermethylation of PTEN was detected using methylation-specific polymerase chain reaction (MS-PCR), expression analysis was performed with immunohistochemistry (IHC) and mutation by direct sequencing in a total of 168 uterine cervix tumor cases. The findings were statistically correlated with the clinical parameters. In addition, the effect of nonsynonymous mutations was studied with molecular dynamics simulations. PTEN promoter hypermethylation (45.8%) was found to be significantly associated with the of PTEN loss (57.14%, P < 0.0001). Tumor stages, tumor size, lymph node (LN) were found to be significantly correlated with both PTEN promoter hypermethylation and PTEN loss. Histological grade, however, showed a significant association with only PTEN loss. In total, 11.76% of tumors exhibited mutations in exon 5 and 7, out of which E150K of exon 5 showed the highest deviations in the crystal structure of PTEN by in silico analysis. This study provides valuable insights into oncology and paves the path in the development of efficient biomarker and/or imperative therapeutic tool for cervical cancer treatment.  相似文献   
86.
We previously reported interferon gamma secretion by human CD4+ and CD8+ T cells in response to recombinant E. coli-expressed Rv1860 protein of Mycobacterium tuberculosis (MTB) as well as protection of guinea pigs against a challenge with virulent MTB following prime-boost immunization with DNA vaccine and poxvirus expressing Rv1860. In contrast, a Statens Serum Institute Mycobacterium bovis BCG (BCG-SSI) recombinant expressing MTB Rv1860 (BCG-TB1860) showed loss of protective ability compared to the parent BCG strain expressing the control GFP protein (BCG-GFP). Since Rv1860 is a secreted mannosylated protein of MTB and BCG, we investigated the effect of BCG-TB1860 on innate immunity. Relative to BCG-GFP, BCG-TB1860 effected a significant near total reduction both in secretion of cytokines IL-2, IL-12p40, IL-12p70, TNF-α, IL-6 and IL-10, and up regulation of co-stimulatory molecules MHC-II, CD40, CD54, CD80 and CD86 by infected bone marrow derived dendritic cells (BMDC), while leaving secreted levels of TGF-β unchanged. These effects were mimicked by BCG-TB1860His which carried a 6-Histidine tag at the C-terminus of Rv1860, killed sonicated preparations of BCG-TB1860 and purified H37Rv-derived Rv1860 glycoprotein added to BCG-GFP, but not by E. coli-expressed recombinant Rv1860. Most importantly, BMDC exposed to BCG-TB1860 failed to polarize allogeneic as well as syngeneic T cells to secrete IFN-γ and IL-17 relative to BCG-GFP. Splenocytes from mice infected with BCG-SSI showed significantly less proliferation and secretion of IL-2, IFN-γ and IL-17, but secreted higher levels of IL-10 in response to in vitro restimulation with BCG-TB1860 compared to BCG-GFP. Spleens from mice infected with BCG-TB1860 also harboured significantly fewer DC expressing MHC-II, IL-12, IL-2 and TNF-α compared to mice infected with BCG-GFP. Glycoproteins of MTB, through their deleterious effects on DC may thus contribute to suppress the generation of a TH1- and TH17-dominated adaptive immune response that is vital for protection against tuberculosis.  相似文献   
87.
The breast cancer metastasis suppressor 1 (BRMS1) is a member of a family of proteins that actively suppress tumour metastasis. Understanding BRMS1 mediated metastasis suppression is critical to the development of new therapies designed to prevent and treat patients with late stage breast cancer. To aid research into the functional aspects that underpin BRMS1 mediated metastasis suppression we have expressed and purified recombinant BRMS1 and produced BRMS1 polyclonal antibodies. Using these antibodies to immunoprecipitate endogenous BRMS1 containing complexes from MCF7 breast cancer cell lines we have identified, by mass spectrometry, the small heat shock protein Hsp27 in complex with BRMS1. We also show that the expression of both BRMS1 and Hsp27 are inversely correlated with metastatic potential.  相似文献   
88.
The post-translational regulation of platelet nitric oxide synthase (NOS) activity is poorly understood. In the present study we examined how tyrosine phosphorylation of NOS, induced by the tyrosine phosphatase inhibitor sodium orthovanadate (VO4), influenced enzyme activity. Platelet NOS was basally tyrosine phosphorylated, but incubation with VO4 (100-1000 microM) led to a concentration-dependent increase in tyrosine phosphorylation of the enzyme with maximal effects observed at 500 microM. Importantly, we observed no change in serine(1179) or threonine(497) phosphorylation. The increased tyrosine phosphorylation was associated with reduced NOS activity and NO bioavailability, as evidenced by measurement of [(3)H]-L-citrulline and cGMP respectively. The signalling events underlying the effects of VO4 were studied using specific inhibitors to kinases that are known to influence NOS activity. Preincubation of platelets with the Src kinase inhibitor PP2 (20 microM) blocked VO4-induced tyrosine phosphorylation of NOS and abolished the effects of VO4 on cGMP formation. The PKC inhibitor Ro-31-8220 (10 microM) had no effect on VO4-induced tyrosine phosphorylation, but did have a modest but significant effect on cGMP formation. In contrast, the PI-3-kinase inhibitor wortmannin (100 nM) had no effect on either tyrosine phosphorylation or cGMP formation. Our data indicate that tyrosine phosphorylation may act to repress NOS activity. Furthermore, VO4 induces a Src-dependent, and to a lesser degree PKC-dependent, inhibition of platelet NOS.  相似文献   
89.
Since 1997, highly pathogenic avian influenza (HPAI) H5N1 virus crossed the species barriers from birds to humans and caused fatal disease, leading to great speculation about a possible influenza pandemic. This subtype is characterized by its pathogenicity in a large number of animal species and resistance to older class of antiviral drugs. At present, two out of three general conditions for the onset of pandemic have been met, emergence of new virus; and its ability to replicate in humans causing serious illness. Next influenza pandemic might be due to human to human transmission. This review addresses the biological and epidemiological aspects of influenza in context of India.  相似文献   
90.
In a sand culture experiment on mustard (Brassica juncea L. Czern. & Coss) cv. Varuna, all tested characteristics at 60 d stage and yield characteristics at harvest were enhanced by K application as its levels increased from 5 to 10, 15, 20, 25, and 30 mM K, with 20 mM K proving best.  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