首页 | 官方网站   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   117篇
  免费   7篇
工业技术   124篇
  2023年   1篇
  2022年   5篇
  2021年   7篇
  2020年   8篇
  2019年   6篇
  2018年   2篇
  2017年   8篇
  2016年   8篇
  2015年   4篇
  2014年   11篇
  2013年   15篇
  2012年   6篇
  2011年   5篇
  2010年   5篇
  2009年   5篇
  2008年   5篇
  2007年   3篇
  2005年   4篇
  2004年   3篇
  2002年   1篇
  1999年   1篇
  1998年   1篇
  1997年   2篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   3篇
  1988年   1篇
  1985年   1篇
排序方式: 共有124条查询结果,搜索用时 468 毫秒
91.
B-cell non-Hodgkin’s lymphoma (NHL) risk associations had been mainly attributed to family history of the disease, inflammation, and immune components including human leukocyte antigen (HLA) genetic variations. Nevertheless, a broad range of genome-wide association studies (GWAS) have shed light into the identification of several genetic variants presumptively associated with B-cell NHL etiologies, survival or shared genetic risk with other diseases. The present review aims to overview HLA structure and diversity and summarize the evidence of genetic variations, by GWAS, on five NHL subtypes (diffuse large B-cell lymphoma DLBCL, follicular lymphoma FL, chronic lymphocytic leukemia CLL, marginal zone lymphoma MZL, and primary central nervous system lymphoma PCNSL). Evidence indicates that the HLA zygosity status in B-cell NHL might promote immune escape and that genome-wide significance variants can give biological insight but also potential therapeutic markers such as WEE1 in DLBCL. However, additional studies are needed, especially for non-DLBCL, to replicate the associations found to date.  相似文献   
92.
In this study, we aimed to optimize the nutritional and environmental conditions for the production of a novel lipase (LBL) from Bacillus licheniformis (GenBank accession no. MT118724). This strain was characterized by morphological and biochemical assays and Sanger sequencing of 16S rDNA. The crude lipolytic activity reached a maximum level 7.5 U mL−1 at 40 °C and pH 8.0 using olive oil as substrate. Additionally, the crude enzyme maintained 100% of its initial activity after incubation for 1 h at 50 °C and pH 9.0. It is mandatory to note that LBL lipase displayed appreciable stability over a wide pH range and extreme temperatures. After purification, the optimal lipolytic activity was observed at pH 8.0 and 40 °C. LBL was shown to be a monomeric protein with an estimated molecular weight of 40 kDa. This novel lipase exhibited high stability and excellent compatibility compared to lipase extracted from Thermomyces lanuginosa (Lipolase® from Novozymes, Denmark) toward various detergents. Washing performance analysis revealed that it efficiently removes tomato sauce stain from cotton cloth. All these interesting enzymatic properties favor this new lipase as a potent candidate for applications in detergent formulations.  相似文献   
93.
The article establishes the basic concepts relating to a novel approach for representing grid analysis data termed “process signatures.” The process signature is the shape of the strain envelope, which depicts the strain state of contiguous elements in a stamping, corresponding to a given forming depth. Apart from inheriting unique process characteristics, the signatures represent the total response of a stamping to the punch and die actions. Reactions to fundamental modes of deformation constitute the building blocks of the signature. The practical importance of this concept stems from the fact that the fundamental blocks (modules) are unique and there is a one-to-one correspondence between areas of the process signature and the punch and die actions. It is further established that the signature responds in a predictable fashion to changes in material, lubricants, tooling clearances, blankholder forces, etc. and that because of this predictability it can be used as a powerful troubleshooting tool. Some practical examples are illustrated to demonstrate the applicability of this approach.  相似文献   
94.
There is a pressing need for high throughput methods to assess potential effects of endocrine disrupting chemicals (EDCs). released into the environment. Currently our ability to identify effects in vitro exceeds that for in vivo monitoring. However, only in vivo analysis provides the full spectrum of physiological impacts exerted by a given chemical. With the aim of finding a physiological system compatible with automatic plate reading we tested the capacity of early embryonic stage Xenopus laevis tadpoles to monitor thyroid hormone (TH) disruption. Fluorescent transgenic X. laevis embryos bearing a TH/bZIP-eGFP construct, placed in 96 well plates, were used for a physiological-based screen for potential TH signaling disruptors. Using stage NF-45 embryos (time of thyroid gland formation) allowed rapid detection of chemical interference with both peripheral TR signaling and production of endogenous TH. Nanomolar concentrations of TH receptor agonists could be detected within 72 h. Moreover, when testing against a 5nM T3 challenge, the effects of inhibitors of TH production were revealed, including inhibitors of TH synthesis, (methimazole: 1 mM or sodium perchlorate: 3.56 microM), as well as antagonists acting at the receptor level (NH3: 2 microM) and a deiodinase inhibitor (iopanoic acid: 10 microM). Finally, we show that the thyroid disrupting activities of BPA (10 microM) and TBBPA (1 microM) can also be detected in this rapid screening protocol. Finally, this noninvasive technology using an automatic reading system shows low variability (around 5%) and permits detection of subtle changes in signaling by EDCs that either inhibit or activate TH signaling in vivo.  相似文献   
95.
In Algeria, little information is available on the population structure of Aspergillus section Flavi in raw materials and resultant animal feeds. A total of 172 isolates belonging to Aspergillus section Flavi were recovered from 57 animal feeds and identified on the basis of macro and micro-morphological characters, mycotoxin production and genetic relatedness. For the molecular analysis, sequencing of the calmodulin gene (CaM) and the internal transcribed spacer (ITS) regions were performed for representative isolates. Four distinct morphotypes were distinguished: Aspergillus flavus (78.5%), Aspergillus tamarii (19.2%), Aspergillus parasiticus (1.7%), and Aspergillus alliaceus (0.6%). All A. flavus isolates were of the L type and no correlation between sclerotia production and aflatoxigenicity was observed. Our results showed that 68% of the A. flavus strains produced aflatoxins B (AFB), and 72.7% were cyclopiazonic acid (CPA) producers. The three isolates of A. parasiticus were able to produce AFB and aflatoxins G but not CPA whereas, all the strains of A. tamarii produced only CPA. The obtained results revealed the presence of different species of Aspergillus section Flavi, among which were aflatoxin producers. This study provides evidence useful for considerations in aflatoxin control strategies.  相似文献   
96.
This study was conducted to compare metals bioaccumulation in the terrestrial isopod Armadillidium granulatum collected from Ghar El Melh lagoon. We focused on recognizing the effects of trace elements on hepatopancreas functional role. To this end, isopod specimens were exposed for 3 weeks to sediments contaminated with cadmium, copper, zinc, mercury, and nickel. Three concentrations were used in duplicate for each experimental condition. At the end of the experiment, metal body burdens were determined using flame atomic absorption spectrometry. Results of the bioaccumulation factor (BAF) showed that the species A. granulatum was classified as a Cu macroconcentrator (BAF > 2) and a Zn deconcentrator (BAF < 2). Dose dependent morphological and histological changes were observed in the hepatopancreas cells using transmission electron microscopy. The predominant features were: microvillus border disruption, condensation of the cytoplasm with increasing endoplasmic reticulum, mitochondria, lysosomes and granules that accumulated metals in B and S cells. The number of lipid droplets decreased especially after Cd, Zn, Hg, and Ni treatments. This study demonstrated that the terrestrial isopod A. gramulatum could be a good indicator of soil metal contamination.  相似文献   
97.
Multidimensional Systems and Signal Processing - This work concerns the resolution of inverse problems encountered in multidimensional signal processing problems. Here, we address the problem of...  相似文献   
98.
This study was designed to assess the impact of the mixture of cadmium (Cd) and zinc (Zn) on the bioaccumulation and the ultrastructural changes in the hepatopancreas of Porcellio laevis (Latreille, 1804) after 4 weeks of exposure to contaminated Quercus leaves under laboratory conditions. For each metal, four concentrations were used with four replicates for each concentration. Metal concentrations in the hepatopancreas and the rest of the body were determined using atomic absorption spectrometry. From the first week until the end of the experiment, a weight gain in P. laevis was observed particularly between the first and the end of exposure from 93.3 ± 18.22 mg fw to 105.22 ± 16.16 mg fw and from 106.4 ± 22.67 mg fw to 125.9 ± 23.9 mg fw for Mix1 and Mix4, respectively. Additionally, the determined metal trace elements (MTE) concentrations in the hepatopancreas were considerably higher compared to those in the rest of the body and seem to be dose‐dependent. Using transmission electron microscopy (TEM), some alterations were highlighted in the hepatopancreas. The main observed alterations were (a) the destruction of the microvilli border in a considerable portion of cells, (b) the increase of the lipid droplets with different shapes and sizes, (c) the increase in the number of the mitochondria, and (d) the appearance of TE in the form of B‐type granules. The obtained results confirmed the ability of P. laevis to deal with high amounts of MTE, suggesting its possible use in future soil's biomonitoring programs.  相似文献   
99.
Journal of Intelligent Manufacturing - Companies are seeking more and more to offer customized goods and services to customers to be able to satisfy their needs. Several methods emerged to fulfill...  相似文献   
100.
Peptides obtained by enzymatic hydrolysis of fish proteins exhibit not only nutritional but also biological properties of dietary uses, or even therapeutic potential. The objective of the present study was to isolate and characterize peptides from the protein hydrolysates of barbel muscle with antibacterial activity against Gram-positive (Listeria monocytogenes, Staphylococcus aureus, Enterococcus faecalis, Micrococcus luteus and Bacillus cereus) and Gram-negative (Escherichia coli, Salmonella enterica, Pseudomonas aeruginosa, Klebsiella pneumoniae and Enterobacter sp.) bacteria. Barbel muscle protein hydrolysates (BMPHs), obtained by treatment with Alcalase® (DH = 6.6%), was fractionated by size exclusion chromatography on a Sephadex G-25 and purified by reversed-phase high performance liquid chromatography (RP-HPLC). The molecular masses and amino acid sequences of these peptides were determined using ESI–MS and ESI–MS/MS, respectively. Eleven peptides in FII-1, FII-2, FII-3 and FII-4 sub-fractions separated by RP-HPLC were identified. The most active peptide fraction (FII-3) contained three peptides: Ala–Ala–Ala–Leu; Ala–Ala–Gly–Gly–Val and Ala–Ala–Val–Lys–Met.  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-23

京公网安备 11010802026262号