全文获取类型
收费全文 | 217篇 |
免费 | 10篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 13篇 |
2018年 | 11篇 |
2017年 | 7篇 |
2016年 | 8篇 |
2015年 | 13篇 |
2014年 | 13篇 |
2013年 | 16篇 |
2012年 | 31篇 |
2011年 | 18篇 |
2010年 | 13篇 |
2009年 | 13篇 |
2008年 | 6篇 |
2007年 | 8篇 |
2006年 | 3篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2000年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有227条查询结果,搜索用时 15 毫秒
81.
The purpose of the present investigation was to produce erythritol by Yarrowia lipolytica mutant without any by-products. Mutants of Y. lipolytica were generated by ultra-violet for enhancing erythrose reductase (ER) activity and erythritol production. The mutants showing the highest ER activity were screened by triphenyl tetrazolium chloride agar plate assay. Productivity of samples was analyzed by thin-layer chromatography and high-performance liquid chromatography equipped with the refractive index detector. One of the mutants named as mutant 49 gave maximum erythritol production without any other by-products (particularly glycerol). Erythritol production and specific ER activity in mutant 49 increased to 1.65 and 1.47 times, respectively, in comparison with wild-type strain. The ER gene of wild and mutant strains was sequenced and analyzed. A general comparison of wild and mutant gene sequences showed the replacement of Asp270 with Glu270 in ER protein. In order to enhance erythritol production, we used a three component-three level-one response Box–Behnken of response surface methodology model. The optimum medium composition for erythritol production was found to be (g/l) glucose 279.49, ammonium sulfate 9.28, and pH 5.41 with 39.76 erythritol production. 相似文献
82.
Retinoic acid induces mouse bone marrow‐derived CD15+, Oct4+ and CXCR4+ stem cells into male germ‐like cells in a two‐dimensional cell culture system 下载免费PDF全文
83.
84.
Jasem Mohamadi Mahsa Motaghi Jafar panahi Mohamad Reza Havasian Ali Delpisheh Mitra Azizian Iraj Pakzad 《Bioinformation》2014,10(11):667-670
The purpose of the present study is to evaluate the sensitivity of Candida species isolated from oral candidiasis and diaper
dermatitis infections in children. The children referring to private and public clinics in Ilam, Iran were exmined for oral candidiasis
and diaper dermatitis. In this study, 248 oral candidiasis and diaper dermatitis samples were collected and cultured.Candida
species were identified by using standard methods. Resistance and sensitivity to amphotericin B, nystatin, ketoconazole,
fluconazole, itraconazole, clotrimazole, and posaconazole were determined using the CLSI M44-A standard disk diffusion method.
From the 248 studied samples, 149 were positive for Candida, among which the Candida albicans was the most prevalent (64.4%).
The resistance of different Candida species to nystatin, itraconazole, fluconazole, ketoconazole, clotrimazole, voriconazole, and
posaconazole were 4, 43, 34.2, 34.9, 21.5, 6, and 6.7%, respectively. No resistance to amphotericin B was observed. Considering
rather low resistance to nystatin, this drug is the best choice for oral candidiasis and diaper dermatitis. 相似文献
85.
In the present study, Hemilepistus elongatus Budde-Lund, 1885 is reported from Iran for the first time, redescribed and its diagnostic characters are figured. This species reveals a high variability in morphological characters. The division of the species at the subspecific level can not be supported anymore. This species differs from other species of the genus by the unique shape of male pleopod-endopodite I. 相似文献
86.
Othman H Gholampour AR Saadat I Farvardin-Jahromoi M Saadat M 《Molecular biology reports》2012,39(3):3299-3303
The aim of this study is to understand the multifactorial causes of age-related macular degeneration (ARMD), and, therefore,
it is reasonable to investigate whether genetic polymorphisms of antioxidant enzymes (GSTM1 and GSTT1) contribute to the development of ARMD. This study consisted of 112 subjects (44 females, 68 males) with exudative ARMD,
who were recruited from Khalili Hospital ophthalmic clinic in Shiraz (southern Iran), referred by vitreoretinal surgeon. Also
112 sex-matched controls (44 females, 68 males) were randomly selected from unrelated volunteers in the same clinic. We excluded
patients and controls with cataract or past history of cataract surgery, asthma, past history of malignancy, cardiovascular
disease that on medication and known cases of glaucoma, because these traits were associated with GSTM1 and/or GSTT1 polymorphisms. There was no association between polymorphisms of neither GSTM1 nor GSTT1 and risk of ARMD. The combination genotypes of GSTM1 and GSTT1 were not associated with the risk of ARMD. We considered the time of deterioration of vision as the time of onset of exudative
ARMD. The Kaplan–Meier analysis revealed that there was significant difference between genotypes of GSTM1 (log rank statistic = 7.03, df = 1, P = 0.008). The age at onset among GSTM1 null genotype was lower than the active genotype of GSTM1. Our results support the hypothesis that the protein encoded by the GSTM1 gene might have a protective function against oxidative stress in retina. Since the age at onset is influenced by the GSTM1 polymorphism, this implies that GSTM1 is a modifier gene. 相似文献
87.
Amiri R Bordbar AK Laurents DV Khosropour AR Mohammadpoor-Baltork I 《International journal of biological macromolecules》2012,50(4):1151-1157
The thermal stability and enzymatic activity of bovine pancreatic ribonuclease A (RNase A) have been investigated in the presence of a homologous series of cationic gemini surfactants (alkanediyl-α,ω-bis(hydroxyethyl methyl hexadecyl ammonium bromide)). UV, circular dichorism and fluorescence spectroscopies have been used for this study. The denaturation curves at various surfactant concentrations were analyzed on basis of a two-transition model to obtain values of T(m) (temperature at the midpoint of denaturation) and ΔH(m) (enthalpy change at T(m)) of each transition. The main conclusion of this study is that these cationic gemini surfactants slightly activate and stabilize RNase A below their critical micelle concentrations at pH 5.0. The cationic gemini surfactant with the shorter spacer interacts more efficiently with RNase A than those with longer spacers. 相似文献
88.
ABSTRACT: Retraction This article [1] has been retracted at the request of the Editor. Although the authors withdrew their submission in order to publish elsewhere, the article was subsequently transmitted to the journal's production department which resulted in it being published in error. 相似文献
89.
Lugg H Sammons RL Marquis PM Hewitt CJ Yong P Paterson-Beedle M Redwood MD Stamboulis A Kashani M Jenkins M Macaskie LE 《Biotechnology letters》2008,30(3):481-491
A strain of Serratia sp. showed intracellular electron-transparent inclusion bodies when incubated in the presence of citrate and glycerol 2-phosphate
without nitrogen source following pre-growth under carbon-limitation in continuous culture. About 1.3 mmol citrate were consumed
per 450 mg biomass, giving a calculated yield of maximally 55% of stored material per g of biomass dry wt. The inclusion bodies
were stained with Sudan Black and Nile Red (NR), suggesting a lipid material, which was confirmed as polyhydroxybutyrate (PHB)
by analysis of molecular fragments by GC and by FTIR spectroscopy of isolated bio-PHB in comparison with reference material.
Multi-parameter flow cytometry in conjunction with NR fluorescence, and electron microscopy, showed that not all cells contained
heavy PHB bodies, suggesting the potential for increasing the overall yield. The economic attractiveness is enhanced by the
co-production of nanoscale hydroxyapatite (HA), a possible high-value precursor for bone replacement materials. 相似文献
90.
Mohammadreza Aflatoonian Iraj Sharifi Behnaz Aflatoonian Ehsan Salarkia Ahmad Khosravi Razieh Tavakoli Oliaee Mehdi Bamorovat Abbas Aghaei Afshar Zahra Babaei Fatemeh Sharifi Moslem Taheri Soodejani Mohammad Reza Shirzadi Mohammad Mehdi Gouya Abolhassan Nadim Hamid Sharifi 《PLoS neglected tropical diseases》2022,16(4)
Negligible data are available following major social activities and environmental changes on leishmaniasis. Therefore, how interactions between these events influence cutaneous leishmaniasis (CL) risk is not well-known. This longitudinal study was undertaken to explore the impact of interventions conducted between 1971 and 2020 in Bam county, which has had the highest disease burden in Iran. Only confirmed CL cases during this period were taken into account. Data were analyzed by SPSS 22 using the X2 test to assess the significance of the difference between proportions. Moreover, we used interrupted time series (ITS) to assess the impact of three environmental events during this period. Overall, 40,164 cases of CL occurred in the past five decades. Multiple complex factors were among the leading causes that synergistically induced the emergence/re-emergence of CL outbreaks in Bam. The main factors attributed negatively to CL control were cessation of malaria spraying activity, expansion of the city spaces, and a massive earthquake creating new breeding potentials for the vectors. The highest impact on CL incidence during these years was related to the earthquake [coefficient = 17.8 (95% CI: 11.3, 22.7); p-value < 0.001]. Many factors can contribute to CL outbreaks in endemic foci. They also can cause new foci in new areas. Since humans are the single reservoir for CL in this area, early detection and effective management significantly contribute to controlling CL to reduce the disease burden. However, essential evidence gaps remain, and new tools are crucial before the disease can ultimately be controlled. Nevertheless, sustained funding and more trained task forces are essential to strengthen surveillance and case management and monitor the interventions’ impact. 相似文献