全文获取类型
收费全文 | 1096篇 |
免费 | 50篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 39篇 |
综合类 | 3篇 |
化学工业 | 362篇 |
金属工艺 | 38篇 |
机械仪表 | 23篇 |
建筑科学 | 30篇 |
矿业工程 | 1篇 |
能源动力 | 55篇 |
轻工业 | 120篇 |
水利工程 | 4篇 |
石油天然气 | 1篇 |
无线电 | 83篇 |
一般工业技术 | 221篇 |
冶金工业 | 26篇 |
原子能技术 | 18篇 |
自动化技术 | 128篇 |
出版年
2023年 | 8篇 |
2022年 | 18篇 |
2021年 | 27篇 |
2020年 | 14篇 |
2019年 | 16篇 |
2018年 | 36篇 |
2017年 | 25篇 |
2016年 | 45篇 |
2015年 | 24篇 |
2014年 | 36篇 |
2013年 | 59篇 |
2012年 | 63篇 |
2011年 | 83篇 |
2010年 | 71篇 |
2009年 | 74篇 |
2008年 | 74篇 |
2007年 | 60篇 |
2006年 | 43篇 |
2005年 | 36篇 |
2004年 | 26篇 |
2003年 | 34篇 |
2002年 | 31篇 |
2001年 | 24篇 |
2000年 | 13篇 |
1999年 | 19篇 |
1998年 | 25篇 |
1997年 | 23篇 |
1996年 | 16篇 |
1995年 | 20篇 |
1994年 | 13篇 |
1993年 | 5篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1988年 | 7篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 4篇 |
1976年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1970年 | 2篇 |
1969年 | 4篇 |
1968年 | 3篇 |
1967年 | 3篇 |
排序方式: 共有1152条查询结果,搜索用时 15 毫秒
971.
972.
Tetsuya Fukuda Hiroyuki Uchida Motoshi Suzuki Hideo Miyamoto Hidetaka Morinaga Hajime Nawata Takayuki Uwajima 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(11):1212-1218
A Trametes villosa laccase, produced as a recombinant protein in Aspergillus oryzae, was purified to an electrophoretically homogeneous state and employed in studies on the metabolism of bisphenol A. Structural analysis of the bisphenol A reaction products by the enzyme indicated that the dimer, trimer, tetramer, pentamer, and hexamer of bisphenol A with C? C and/or C? O bonds between phenol moieties, were formed as the result of successive oxidative‐condensation. The reaction mixture also contained oligomers fragments, each with phenol molecules, suggesting the occurrence of cleavage of the formed oligomers to release 4‐isopropenylphenol. A luciferase reporter assay using COS‐7 cells revealed that both the soluble and insoluble fractions of the bisphenol A reaction products had no estrogenic activity even at rather high concentrations. Copyright © 2004 Society of Chemical Industry 相似文献
973.
Bacterial microflora of carp (Cyprinus carpio) and its shelf-life extension by essential oil compounds 总被引:2,自引:0,他引:2
Barakat S. M. Mahmoud Koji Yamazaki Kazuo Miyashita Shin Il-Shik Chang Dong-Suk Tetsuya Suzuki 《Food microbiology》2004,21(6):657-666
The microflora of common carp (Cyprinus carpio) skin, gill and intestine were analysed and the antimicrobial activities of garlic oil and nine constituents of essential oils (allyl isothiocyanate, carvacrol, cinnamaldehyde, citral, cuminnaldehyde, eugenol, isoeugenol, linalool and thymol) against the carp isolates were studied to identify compounds that might extend the shelf-life of carp fillet. A total of 90 isolated strains were identified to belong to seven genera: Acinetobacter (6), Alcaligenes (2), Bacillus (2), Flavobacterium (20), Micrococcus (2), Moraxella (6) and Pseudomonas (4), and two families Enterobacteriaceae (14) and Vibrionaceae (34). The dominant micro-organisms of carp were found to be Flavobacterium (37%) and Vibrionaceae (33%) in skin, Flavobacterium (33%) in gill and Vibrionaceae (63%) and Flavobacterium (37%) in intestine. Against these isolates, thymol, carvcarol and cinnamaldehyde had the strongest antimicrobial activities, followed by isoeugenol, eugenol, garlic oil, and then citral. The antimicrobial properties of the other constituents tested (cuminnaldehyde, linalool and allyl isothiocyanate) were low. In tests of mixed compounds, a combination of carvacrol and thymol had the highest antimicrobial activity. Moraxella, Flavobacterium and Vibrionaceae were more sensitive to the compounds, whereas Alcaligenes strains were resistant. Dipping carp fillets in a solution of 0.5% carvacrol and 0.5% thymol before storage at 5°C and 10°C reduced both the total microbial load by about 100-fold and the Volatile Bases Nitrogen (VB-N), as compared with controls. In addition, dipping treatment delayed bacterial growth and extended the shelf-life of the fillets from 4 to 12 days at low temperature (5°C). However, the treated and control fillets showed little difference during storage at 10°C. Data from sensory evaluation showed that dipped fillets in 1% (carvacrol+thymol) extended the shelf-life of carp fillets by 8 and 4 days at 5° and 10°C, respectively. Thus, carvacrol and thymol dipping can improve the microbial stability of fish fillets by removing bacteria and by inhibiting bacterial growth. 相似文献
974.
Spherically contoured AT-cut rectangular quartz crystal resonators have been fabricated by electro-magnetically enforced rotary barrel finishing system. Shape and frequency responses of the fabricated blanks have also been measured and compared with those of the blanks fabricated without using the electro-magnets. In previous work by the authors, the fixed abrasive method, in which abrasive papers are used instead of powder abrasives, was introduced as a new rotary barrel finishing method for fabricating the spherically contoured rectangular quartz crystal blanks. By adopting the fixed abrasive method, accurate shape transferring, dustless clean working environment, and short turnaround time has been realized. In this paper, in order to further shorten the process time, electro-magnets are used for generating additional machining pressure. As a result, the process time required for complete shape transferring has been decreased to 67% of the turnaround time obtained by previous work. 相似文献
975.
976.
Yamauchi Asao; Nakashima Toshihiro; Tokuriki Nobuhiko; Hosokawa Masato; Nogami Hideki; Arioka Shingo; Urabe Itaru; Yomo Tetsuya 《Protein engineering, design & selection : PEDS》2002,15(7):619-626
A directed evolution with phage-displayed random polypeptidesof about 140 amino acid residues was followed until the sixthgeneration under a selection based on affinity to a transitionstate analog for an esterase reaction. The experimental designdeliberately limits the observation to only 10 clones per generation.The first generation consists of three soluble random polypeptidesand seven arbitrarily chosen clones from a previously constructedlibrary. The clone showing the highest affinity in a generationwas selected and subjected to random mutagenesis to generatevariants for the next generation. Even within only 10 arbitrarilychosen polypeptides in each of the generations, there are enoughvariants in accord to capacity of binding affinity. In addition,the binding capacity of the selected polypeptides showed a gradualcontinuous increase over the generation. Furthermore, the purifiedselected random polypeptides exhibited a gradual but significantincrease in esterase activity. The ease of the functional developmentwithin a small sequence variety implies that enzyme evolutionis prompted even within a small population of random polypeptides. 相似文献
977.
Two Major Bile Acids in the Hornbills, (24R,25S)-3α,7α,24-Trihydroxy-5β-cholestan-27-oyl Taurine and Its 12α-Hydroxy Derivative
下载免费PDF全文
![点击此处可从《Lipids》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rika Satoh Hiroaki Ogata Tetsuya Saito Biao Zhou Kaoru Omura Satoshi Kurabuchi Kuniko Mitamura Shigeo Ikegawa Lee R. Hagey Alan F. Hofmann Takashi Iida 《Lipids》2016,51(6):757-768
Two major bile acids were isolated from the gallbladder bile of two hornbill species from the Bucerotidae family of the avian order Bucerotiformes Buceros bicornis (great hornbill) and Penelopides panini (Visayan tarictic hornbill). Their structures were determined to be 3α,7α,24‐dihydroxy‐5β‐cholestan‐27‐oic acid and its 12α‐hydroxy derivative, 3α,7α,12α,24‐tetrahydroxy‐5β‐cholestan‐27‐oic acid (varanic acid, VA), both present in bile as their corresponding taurine amidates. The four diastereomers of varanic acid were synthesized and their assigned structures were confirmed by X‐ray crystallographic analysis. VA and its 12‐deoxy derivative were found to have a (24R,25S)‐configuration. 13 additional hornbill species were also analyzed by HPLC and showed similar bile acid patterns to B. bicornis and P. panini. The previous stereochemical assignment for (24R,25S)‐VA isolated from the bile of varanid lizards and the Gila monster should now be revised to the (24S,25S)‐configuration. 相似文献
978.
Fatigue crack retardation with infiltrated SiC paste into a crack is examined in low carbon structural steel. Two different sizes of SiC powders, whose average diameters are 15 and 53 μm, are used. The SiC powder mixed with oil is infiltrated into a through thickness fatigue crack from the crack mouth. Fatigue crack growth retardation is examined by the ΔK increasing test of R = 0.1, comparing with the base plate property, where ΔK is stress intensity factor range and R is stress ratio. Crack growth is retarded just after infiltrating SiC paste into the crack mouth, and the deceleration of crack growth rate to 1/50 of the base plate appears in the maximum. It is revealed that this crack retardation behaviour results from the crack closure induced by the wedge effect of the SiC particle into a crack. The crack retardation effect is investigated with several combinations of SiC particle size and cyclic stress conditions. The crack growth rate, da/dn and stress intensity factor, Kcl for the crack closure depend on both the maximum stress intensity factor, Kmax, and the stress ratio, R. While the better retardation effect can appear in the higher Kmax and the higher R ratio, it disappears in the R ratio over 0.7. The SiC paste with 15 μm powder brings the crack retardation effect in the wider cyclic stress condition more stable than in the SiC paste with 53 μm powder. 相似文献
979.
In Situ Bond Modulation of Graphitic Carbon Nitride to Construct p–n Homojunctions for Enhanced Photocatalytic Hydrogen Production
下载免费PDF全文
![点击此处可从《Advanced functional materials》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Guigao Liu Guixia Zhao Wei Zhou Yanyu Liu Hong Pang Huabin Zhang Dong Hao Xianguang Meng Peng Li Tetsuya Kako Jinhua Ye 《Advanced functional materials》2016,26(37):6822-6829
Graphitic carbon nitride (g‐C3N4) has recently emerged as an attractive photocatalyst for solar energy conversion. However, the photocatalytic activities of g‐C3N4 remain moderate because of the insufficient solar‐light absorption and the fast electron–hole recombination. Here, defect‐modified g‐C3N4 (DCN) photocatalysts, which are easily prepared under mild conditions and show much extended light absorption with band gaps decreased from 2.75 to 2.00 eV, are reported. More importantly, cyano terminal C?N groups, acting as electron acceptors, are introduced into the DCN sheet edge, which endows the DCN with both n‐ and p‐type conductivities, consequently giving rise to the generation of p–n homojunctions. This homojunction structure is demonstrated to be highly efficient in charge transfer and separation, and results in a fivefold enhanced photocatalytic H2 evolution activity. The findings deepen the understanding on the defect‐related issues of g‐C3N4‐based materials. Additionally, the ability to build homojunction structures by the defect‐induced self‐functionalization presents a promising strategy to realize precise band engineering of g‐C3N4 and related polymer semiconductors for more efficient solar energy conversion applications. 相似文献
980.
Hiromasa Nakayama Tetsuya Takemi Haruyasu Nagai 《Journal of Nuclear Science and Technology》2016,53(6):887-908
We have developed a LOcal-scale High-resolution atmospheric DIspersion Model using Large-Eddy Simulation (LOHDIM-LES) to assess the safety at nuclear facilities and to respond to emergency situations resulting from accidental or deliberate releases of radioactive materials (e.g., a terrorist attack in an urban area). In parts 1–4, LESs of turbulent flows and plume dispersion over a flat terrain, around an isolated building, within building arrays with different obstacle densities, and within an actual urban area were performed, which showed the basic performance comparable to wind tunnel experimental technique. In this study, we extend the LOHDIM-LES to turbulent flows and plume dispersion in an actual urban area under real meteorological conditions by coupling with a meso-scale meteorological simulation model. The LES results of wind speed, wind direction, and concentration values are generally reproduced well. It is concluded that our coupling approach between LES and meso-scale meteorological models is effective in detailed simulations of turbulent flows and plume dispersion in urban areas under real meteorological conditions. 相似文献