全文获取类型
收费全文 | 1025篇 |
免费 | 60篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 10篇 |
综合类 | 4篇 |
化学工业 | 535篇 |
金属工艺 | 18篇 |
机械仪表 | 27篇 |
建筑科学 | 31篇 |
矿业工程 | 4篇 |
能源动力 | 28篇 |
轻工业 | 65篇 |
水利工程 | 3篇 |
石油天然气 | 10篇 |
武器工业 | 2篇 |
无线电 | 28篇 |
一般工业技术 | 192篇 |
冶金工业 | 52篇 |
原子能技术 | 3篇 |
自动化技术 | 78篇 |
出版年
2023年 | 17篇 |
2022年 | 166篇 |
2021年 | 101篇 |
2020年 | 34篇 |
2019年 | 25篇 |
2018年 | 46篇 |
2017年 | 38篇 |
2016年 | 44篇 |
2015年 | 25篇 |
2014年 | 40篇 |
2013年 | 58篇 |
2012年 | 56篇 |
2011年 | 73篇 |
2010年 | 42篇 |
2009年 | 53篇 |
2008年 | 46篇 |
2007年 | 33篇 |
2006年 | 24篇 |
2005年 | 31篇 |
2004年 | 17篇 |
2003年 | 19篇 |
2002年 | 29篇 |
2001年 | 12篇 |
2000年 | 11篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 2篇 |
1995年 | 7篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1975年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有1090条查询结果,搜索用时 31 毫秒
91.
Kinetics and mechanism of low-temperature ozone decomposition by Co-ions adsorbed on silica 总被引:3,自引:0,他引:3
Tatiana L. Rakitskaya Alim A. Ennan Irina V. Granatyuk Alexander Yu. Bandurko Gilbert G. A. Balavoine Yurii V. Geletii V. Ya. Paina 《Catalysis Today》1999,53(4):616-723
Kinetics and mechanism of low-temperature ozone ((5–50) × 10−3 mol/m3 in the gas–air mixture) decomposition by Co-catalysts supported on silica have been studied. Co-ions adsorbed on silica react with surface oxygen species, thus resulting in an active catalyst. Low concentrations of Co-ions form a monolayer on the surface. Their specific catalytic activity remained constant, but sharply decreased at higher concentrations due to a formation of polynuclear Co-complexes. Ozone decomposition may occur either as a stoichiometric or catalytic process, depending on the ozone and catalyst concentrations. The turnover number increases with ozone concentration reaching a saturation point. It also increases with Co-concentration in the beginning, but drops at a concentration >1 × 10−4 mol/g. The mechanism of the reaction is discussed. 相似文献
92.
93.
94.
Andrei E Filonov Irina F Puntus Alexander V Karpov Irina A Kosheleva Konstantin I Kashparov Anatoly V Slepenkin Alexander M Boronin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(6):562-569
The efficiency of naphthalene degradation by Pseudomonas putida G7 in soil was assessed using a mathematical model. The number of microorganisms and the concentration of naphthalene in soil samples were monitored. The feasibility of a spectrofluorometric method for naphthalene assay in soil samples was compared with high pressure liquid chromatography. A proposed mathematical model described the growth of the naphthalene‐degrading strains and the consumption of substrates (naphthalene, naphthalene degradation intermediates and soil organic substances) in soil. To describe the growth kinetics of microorganisms having high affinity to substrates with low solubility, two differential equations with substrate exponent 2/3 were proposed. These equations were used to describe utilization of soil organic matter. The model parameters characterize the growth rates for different substrates and respective yield coefficients, specific bacterial death and adaptation rates, and also the rates of PAHs degradation and evaporation. These characteristics can be used in choosing the bacterial strains for biopreparations and efficient clean‐up biotechnology of polluted soils. Copyright © 2004 Society of Chemical Industry 相似文献
95.
Electrochemical and thermal properties of graphite electrodes with imidazolium- and piperidinium-based ionic liquids 总被引:1,自引:0,他引:1
Irina A. Profatilova Nam-Soon Choi Sae Weon Roh Sung Soo Kim 《Journal of power sources》2009,192(2):636-643
The electrochemical and thermal properties of graphite electrodes with electrolytes containing 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (EMITFSI) and N-methyl,N-propylpiperidinium bis(trifluoromethanesulfonyl)imide (MPPpTFSI) ionic liquids are investigated. The ionic liquids undergo extensive reductive decomposition on a graphite electrode during the first charge. The effect of a fluoroethylene carbonate (FEC) additive on the reductive decomposition of the ionic liquids is examined by electrochemical, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX) analysis. Thermal reactions between a lithiated graphite electrode and an ionic liquid-containing electrolyte are investigated with differential scanning calorimetry (DSC). The introduction of an ionic liquid can effectively reduce the exothermic heat evolution from the thermal reactions between a lithiated graphite electrode and an electrolyte. 相似文献
96.
The preparation and characterization of oligothienylene dialdehydes and related soluble copolymers in which thenylenic segments regularly alternate with phenylenic portions linked by azomethine moieties is presented. The polymer series with three, six and eight thienylenic residues showed interesting evidences of electronic confinement in low-gap segments (thienylenic). Self-assembled structures of oligomers can be obtained either by evaporation in high vacuum or by a proper thermal treatment of spin coated films, depending on the molecule length. Polymers prepared by different synthetic routes show different thermal and structural properties as a function of the ratio of two possible isomers at imino linkage. The order degree also influences the optical properties in fact luminescence data are strictly related to the percentage of the two isomers. 相似文献
97.
Elena N Konyushenko Jaroslav Stejskal Ivana ednkov Miroslava Trchov Irina Sapurina Miroslav Cieslar Jan Proke 《Polymer International》2006,55(1):31-39
The courses of aniline oxidation with ammonium peroxydisulfate in aqueous solutions of strong (sulfuric) and in weak (acetic) acids, followed by temperature and acidity changes, are different. In solutions of sulfuric acid, granular polyaniline (PANI) was produced; in solutions of acetic acid, PANI nanotubes were obtained. The external diameter of the nanotubes was 100–300 nm, the internal cavity 20–100 nm, and the length extended to several micrometres. The morphology of PANI, granular or tubular, depends on the acidity conditions during the reaction rather than on the chemical nature of the acid. PANI nanotubes were also produced when aniline was oxidized in the absence of any acid. The bulk conductivity of PANI prepared in solutions of acetic acid was 0.08–0.27 S cm?1, depending on the acid concentration. Protonated PANI prepared in sulfuric and acetic acids were deprotonated with ammonium hydroxide to obtain PANI bases and the ammonium salt of the protonating acid. FTIR spectroscopy showed the differences in the molecular structure of the PANI bases. Irrespective of whether the polymerization was performed in solutions of sulfuric or acetic acid, PANI had hydrogen sulfate counter‐ions only. The PANI morphology is thus not controlled by the nature of counter‐ions. The acidity of the reaction medium determines the protonation of monomer, oligomer and polymer species. The chemistry of aniline oxidation is likely to be affected especially by the protonation of an intermediate in the pernigraniline form. It is proposed that, in the course of aniline oxidation, pH‐dependent self‐assembly of aniline oligomers predetermines the final PANI morphology. Copyright © 2005 Society of Chemical Industry 相似文献
98.
Vitaly V. Kushnirov Michael D. Ter-Avanesyan Svetlana A. Didichenko Vladimir N. Smirnov Yuri O. Chernoff Irina L. Derkach Olga N. Novikova Sergey G. Inge-Vechtomov Michael A. Neistat Ilya I. Tolstorukov 《Yeast (Chichester, England)》1990,6(6):461-472
SUP2(SUP35) is an omnipotent suppressor gene, coding for an EF-1α-like protein factor, intimately involved in the control of translational accuracy in yeast Saccharomyces cerevisiae. In the present study a SUP2 gene analogue from yeast Pichia pinus was isolated by complementation of the temperature-sensitive sup2 mutation of S. cerevisiae. The nucleotide sequence of the SUP2 gene of P. pinus codes for a protein of 82·4 kDa, exceeding the Sup2 protein of S. cerevisiae by 6 kDa. Like the SUP2 gene product of S. cerevisiae, the Sup2 protein of P. pinus represents a fusion of a unique N-terminal part of a region homologous to EF-1α. The comparison of amino acid sequences of the Sup2 proteins reveals high conservations (76%) of the C-terminal region and low conservation (36%) of the N-terminal part where, in addition, the homologous correspondence is ambiguous. Proteins related to the Sup2 of S. cerevisiae where found in P. pinus and some other yeast species by the immunoblotting technique. The relation between the evolutionary conservation of different regions of the Sup2 protein and their functional significance is discussed. 相似文献
99.
Irina Kalinina Elena Bekyarova Qingxiao Wang Yas Fadel Al-Hadeethi Xixiang Zhang Faisel Al-Agel 《Fullerenes, Nanotubes and Carbon Nanostructures》2014,22(1-3):47-53
We report the formation of chromium clusters on the outer walls of single-walled carbon nanotubes (SWNTs). The clusters were obtained by reacting purified SWNTs with chromium hexacarbonyl in dibutyl ether at 100°C. The functionalized SWNTs were characterized by thermogravimetic analysis, XPS, and high-resolution TEM. The curvature of the SWNTs and the high mobility of the chromium moieties on graphitic surfaces allow the growth of the metal clusters and we propose a mechanism for their formation. 相似文献
100.
Andrew J. Coughlin Jeyarama S. Ananta Nanfu Deng Irina V. Larina Paolo Decuzzi Jennifer L. West 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(3):556-565
Multimodal imaging offers the potential to improve diagnosis and enhance the specificity of photothermal cancer therapy. Toward this goal, gadolinium‐conjugated gold nanoshells are engineered and it is demonstrated that they enhance contrast for magnetic resonance imaging, X‐ray, optical coherence tomography, reflectance confocal microscopy, and two‐photon luminescence. Additionally, these particles effectively convert near‐infrared light to heat, which can be used to ablate cancer cells. Ultimately, these studies demonstrate the potential of gadolinium‐nanoshells for image‐guided photothermal ablation. 相似文献