全文获取类型
收费全文 | 128篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
综合类 | 5篇 |
化学工业 | 38篇 |
建筑科学 | 11篇 |
能源动力 | 27篇 |
轻工业 | 15篇 |
石油天然气 | 1篇 |
一般工业技术 | 6篇 |
冶金工业 | 4篇 |
原子能技术 | 5篇 |
自动化技术 | 16篇 |
出版年
2023年 | 3篇 |
2022年 | 2篇 |
2021年 | 3篇 |
2020年 | 1篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 5篇 |
2016年 | 1篇 |
2015年 | 4篇 |
2014年 | 4篇 |
2013年 | 6篇 |
2012年 | 7篇 |
2011年 | 8篇 |
2010年 | 11篇 |
2009年 | 11篇 |
2008年 | 8篇 |
2007年 | 5篇 |
2006年 | 11篇 |
2005年 | 8篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 6篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1998年 | 1篇 |
1996年 | 1篇 |
1995年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1984年 | 1篇 |
排序方式: 共有130条查询结果,搜索用时 15 毫秒
1.
通过水培和土壤盆栽试验,研究了Ca对茶树F吸收的影响。结果显示,在含F溶液中添加Ca显著降低茶树对F的吸收。在土壤盆栽试验中也得到了类似结果,在2种土壤F含量条件下,加入Ca(NO3)2后显著降低茶树成熟叶和新梢F含量。同样土壤加入CaO后,显著降低茶树对F的吸收。土壤分析表明加入Ca(NO3)2后并没有显著改变土壤水溶性F含量,而加入CaO后还增加了土壤水溶性F含量。因此,Ca减少F吸收可能并不单纯是因为形成CaF2后降低土壤F的有效性。 相似文献
2.
An increase in hydrogen evolution from the hydrogen-evolving enzyme in the actinomycete Frankia was recorded in the presence of nickel. Immunogold localisation analysis of the intracellular distribution of hydrogenase proteins indicated that they were evenly distributed in the membranes and cytosol of both hyphae and vesicles. In addition, molecular characterisation of the hydrogen-evolving enzyme at the proteomic level, using two-dimensional gel electrophoresis combined with mass spectrometry, confirmed that the Frankia hydrogen-evolving enzyme is similar to the cyanobacterial bidirectional hydrogenase of Anabena siamensis. 相似文献
3.
4.
It is essential to predict the treatment efficacy of pancreatic carcinoma early.The purpose of this study was to examine whether ~(18)F-FDG(2'-deoxy-2'-[~(18)F]fiuoro-D-glucose) or ~(18)F-FLT(3'-deoxy-3'-~(18)F-fluorothymidine) PET can be used for chemosensitivity testing by investigating the binding characteristic of ~(18)F-FDG or ~(18)F-FLT with Patu 8988 human pancreatic carcinoma cell and the influence of gemcitabine in the uptake of ~(18)F-FDG or ~(18)F-FLT on Patu 8988.Under the conditions of 1×10~... 相似文献
5.
6.
Natural Abundance Carbon Isotopic Analysis Indicates the Equal Contribution of Local Synthesis and Plasma Uptake to Palmitate Levels in the Mouse Brain 下载免费PDF全文
R. J. Scott Lacombe Vanessa Giuliano Raphaël Chouinard‐Watkins Richard P. Bazinet 《Lipids》2018,53(5):481-490
Saturated fatty acids are the most abundant fatty acids in the brain, however, there has been some debate regarding the ability of intact dietary saturated fatty acids to be incorporated into the brain. In the present study, we use compound specific isotope analysis to measure the natural abundance carbon isotopic signature of brain, liver, and blood palmitic acid (PAM) and compare it to the dietary PAM and sugar isotopic signatures to calculate the relative contribution of both the incorporation of intact and endogenously synthesized PAM to these pools. Mice were equilibrated to the study diet, and extracted fatty acids were analyzed with gas chromatography isotope ratio mass spectrometry to determine the carbon isotopic signature of PAM (δ13CPAM). Liver, serum total, and serum unesterified fatty acid δ13CPAM ranged between ?20.6 and ?21.1 mUr and were approximately 8.5 mUr more enriched in 13C when compared to the dietary PAM signature. Brain δ13CPAM was found to be more enriched than liver or blood pools (?16.7 ± 0.2 mUr, mean ± SD). Two end‐member‐mixed modeling using the carbon isotopic signature of dietary PAM and dietary sugars determined the contribution of synthesis to the total tissue PAM pool to range between 44% and 48%. This suggests that endogenous synthesis and dietary PAM are near equal contributors to brain, liver, and blood PAM pools. In conclusion, our data provide evidence that brain PAM levels are maintained by both local endogenous synthesis and through the uptake of intact PAM from the blood. 相似文献
7.
Ultradispersed particles in heavy oil: Part I, preparation and stabilization of iron oxide/hydroxide
Nashaat N. Nassar 《Fuel Processing Technology》2010,91(2):164-1023
In this study, ultradispersed colloidal particles of iron oxide/hydroxide were prepared in-situ in heavy oil matrices adopting (w/o) microemulsion approach for nanoparticle preparation detailed in our previous work [1-3]. The effect of composition of heavy oil on the stable concentration of colloidal particles, particle uptake, was investigated. The following trends in particle uptake were common between the (w/o) microemulsions and the heavy oil matrices. An optimum water content was found for which a maximum particle uptake was attained. Particle uptake increased as the content of vacuum residue, VR, and precursor salt concentration increased. Vacuum residue contributes high asphaltene content, which acts as a surface active agent. The iron oxide/hydroxide particles had been recently shown to effectively remove H2S(g) from oil phase [4]. H2S(g) is a hazardous by-product of heavy oil recovering and upgrading which should be removed as soon as it forms. Results pertaining to H2S(g) removal from heavy oil employing ultradispersed particles are communicated in Part II of this study. 相似文献
8.
Our previous work proved that high adsorption capacity and uptake rate of lysozyme were achieved on alginate(Alg)-grafted re sin with an ionic capacity(IC) of 240 mmol·L~(-1)(Alg-FF-240).Moreover,the salt-tolerant feature of Alg-FF-230 was improved by using sequential alginate grafting and sulfonation strategy.Inspired by the enhanced adsorption performance of lysozyme,we have herein proposed to investigate the static and dynamic adsorption behaviors of γ-globulin on a series of Alg-grafted resins with different grafting densities and sulfonation degrees.The adsorption ca pacity of γ-globulin decreased with increa sing alginate-grafting density(IC) from 160 to 230 mmol·L~(-1) at 0 mmol·L~(-1) NaCl because of the steric hindrance caused by the alginate-grafting layer.Effects of ionic strength(IS) indicated that the adsorption capacities of the resins with the IC value of 230-370 mmol·L~(-1) were much higher than CM Sepharose FF at 50-100 mmol·L~(-1) NaCl,and the uptake rate of Alg-FF-230 was about twice as much as that of CM Sepharose FF.This work demonstrated the important effects of alginate-grafting layer and IS in γ-globulin adsorption behavior,which would be helpful in the design of Alggrafted resins and the selection of proper IS condition for protein purification. 相似文献
9.
Ki-Seok YoonKeiichi Fukuda Kiyoshi Fujisawa Hirofumi Nishihara 《International Journal of Hydrogen Energy》2011,36(12):7081-7088
The membrane-bound [NiFe]-hydrogenase from Hydrogenovibrio marinus (HmMBH) was purified homogeneously under anaerobic conditions. Its molecular weight was estimated as 110 kDa, consisting of a heterodimeric structure of 66 kDa and 37 kDa subunits. The purified enzyme exhibited high activity in a wide temperature range: 185 U/mg at 30 °C and 615 U/mg at 85 °C (the optimum temperature). The Km and kcat/Km values for H2 were, respectively, 12 μM and 8.58 × 107 M−1 s−1. The optimum reaction pH was 7.8, but its stability was particularly high at pH 4.0-7.0. Results show that HmMBH was remarkably thermostable and oxygen-resistant: its half-life was 75 h at 80 °C under H2, and more than 72 h at 4 °C under air. The air-oxidized HmMBH for 72 h showed only weak EPR signals of Ni-B, suggesting a structural feature in which the active center is not easily oxidized. 相似文献
10.
在田间以不同处理进行甘蔗吸S试验,结果表明:不同处理间甘蔗吸收S素养分量为:1.16~1.54 g/kg,且各处理间差异不显著;施用S素肥料对甘蔗有一定的增产效果,施S各处理比CK(不施S)增产1.12%~9.82%,以处理NPKS2施用量60 kg/hm2效果较佳,增产9.82%。甘蔗S吸收量在1.16~1.21 g/kg范围内与甘蔗产量呈正效应,过之则呈负效应;甘蔗吸收S素养分量的临界值为1.21 g/kg;甘蔗施用S肥的当季肥料利用率为19.10%。 相似文献