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排序方式: 共有257条查询结果,搜索用时 15 毫秒
61.
The effects of oxygen supply conditions and specific biofilm interfacial area on the phenol removal rate in a three‐phase fluidized bed bioreactor were evaluated. The experimental data were well‐explained by the semi‐theoretical equation based on the assumption that the reaction rate follows first‐order reaction kinetics with respect to oxygen and zero‐order one with respect to phenol. Two cases, biological reaction as rate‐controlling step and oxygen absorption as rate‐controlling step, were both explicable by this semi‐theoretical equation. The maximum volumetric phenol removal rate was 27.4 kg·m?3·d?1. 相似文献
62.
Aryl Polyenes,a Highly Abundant Class of Bacterial Natural Products,Are Functionally Related to Antioxidative Carotenoids 下载免费PDF全文
Tim A. Schöner Dr. Sören Gassel Ayako Osawa Dr. Nicholas J. Tobias Yukari Okuno Yui Sakakibara Prof. Kazutoshi Shindo Prof. Gerhard Sandmann Prof. Helge B. Bode 《Chembiochem : a European journal of chemical biology》2016,17(3):247-253
Bacterial pigments of the aryl polyene type are structurally similar to the well‐known carotenoids with respect to their polyene systems. Their biosynthetic gene cluster is widespread in taxonomically distant bacteria, and four classes of such pigments have been found. Here we report the structure elucidation of the aryl polyene/dialkylresorcinol hybrid pigments of Variovorax paradoxus B4 by HPLC‐UV‐MS, MALDI‐MS and NMR. Furthermore, we show for the first time that this pigment class protects the bacterium from reactive oxygen species, similarly to what is known for carotenoids. An analysis of the distribution of biosynthetic genes for aryl polyenes and carotenoids in bacterial genomes is presented; it shows a complementary distribution of these protective pigments in bacteria. 相似文献
63.
Methods for parallel computation of complex flow problems 总被引:1,自引:0,他引:1
This paper is an overview of some of the methods developed by the Team for Advanced Flow Simulation and Modeling (TAFSM) [http://www.mems.rice.edu/TAFSM/] to support flow simulation and modeling in a number of “Targeted Challenges”. The “Targeted Challenges” include unsteady flows with interfaces, fluid–object and fluid–structure interactions, airdrop systems, and air circulation and contaminant dispersion. The methods developed include special numerical stabilization methods for compressible and incompressible flows, methods for moving boundaries and interfaces, advanced mesh management methods, and multi-domain computational methods. We include in this paper a number of numerical examples from the simulation of complex flow problems. 相似文献
64.
Masatake Kawada Zen‐ichiro Kawasaki Kenji Matsu‐ura Satoru Kuroki Teruya Osawa Hiroki Tanaka 《Electrical Engineering in Japan》2000,131(4):38-43
Partial discharge (PD) within voids in solid insulating systems is a symptom and/or a direct cause of a deterioration of stator windings of a turbine generator. The bandwidth of the electromagnetic waves emitted from PD is very broad and ranges to the gigahertz. We developed a new system based on the spatial phase difference method for detecting microwaves (GHz) emitted from PD. In this paper we applied this system to two off‐line turbine generators in the overhaul and an on‐line turbine generator which has two built‐in antennas. On‐line PD detection of the turbine generator is very useful for recognizing abnormal and/or deteriorated stator winding insulation without a machine outage. It was found that the detection system was able to detect microwaves emitted from PD in an operating turbine generator. © 2000 Scripta Technica, Electr Eng Jpn, 131(4): 38‐43, 2000 相似文献
65.
H Fujii T Sato S Kaneko O Gotoh Y Fujii-Kuriyama K Osawa S Kato H Hamada 《Canadian Metallurgical Quarterly》1997,16(14):4163-4173
Retinoic acid (RA) is a physiological agent that has a wide range of biological activity and appears to regulate developmental programs of vertebrates. However, little is known about the molecular basis of its metabolism. Here we have identified a novel cytochrome P450 (P450RA) that specifically metabolizes RA. In vitro, P450RA converts all-trans RA into 5,8-epoxy all-trans RA. P450RA metabolizes other biologically active RAs such as 9-cis RA and 13-cis RA, but fails to metabolize their precursors, retinol and retinal. Overexpression of P450RA in cell culture renders the cells hyposensitive to all-trans RA. These functional tests in vitro and in vivo indicate that P450RA inactivates RA. The P450RA gene is not expressed uniformly but in a stage- and region-specific fashion during mouse development. The major expression domains in developing embryos include the posterior neural plate and neural crest cells for cranial ganglia. The expression of P450RA, however, is not necessarily inducible by excess RA. These results suggest that P450RA regulates the intracellular level of RA and may be involved in setting up the uneven distribution of active RA in mammalian embryos. 相似文献
66.
Soy isoflavonoids have many useful properties. However, they are metabolized in vivo, including in humans. The effect of the metabolism of soy isoflavonoids on their properties is not fully understood. We have isolated the bacterial strain SY8519, which has been shown to metabolize daidzein to O-desmethylangolensin and to produce 2-(4-hydroxyphenyl)propionic acid from genistein. According to chiral HPLC analysis, the 2-(4-hydroxyphenyl)propionic acid obtained from the bacterium was optically active. To determine the absolute stereochemistry of the microbial product, we prepared (S)-2-(4-hydroxyphenyl)propionic acid from (S)-2-phenylpropionic and concluded that the microbial product had an R-configuration by chiral HPLC analysis. We also applied the metabolite to mouse adipocytes and found that 2-HPPA was less effective at reducing leptin secretion than the parent compound genistein. Our results suggested that ‘O-desmethylangolensin-production’ attenuates the effect of soy isoflavonoids by reducing not only the activity of daidzein but also that of genistein. 相似文献
67.
Tomo Osawa Atsushi Sogabe Masayuki Shirao Shuji Nishihama Isamu Kaneda† Shin-ichi Yusa‡ 《International journal of cosmetic science》2009,31(6):479-479
IFSCC Magazines , 12 (2009) (1) 3–7
It is generally well known that the surface of an inorganic UV-protective powder used in a sunscreen formula is treated with a fatty acid or other hydrophobic chemicals to obtain a high water resistance. Due to the resulting strongly hydrophobic surface, the treatment has a clear drawback in that it allows the sunscreen to leave its base components on the skin after washing with regular soap. Therefore, in this study to develop an intelligent sunscreen formula that has a high water resistance and can be washed away easily with regular soap, we focused on a pH-responsive polymer as the surface-treatment agent for a UV-protective powder. Numerous experiments led to the synthesis of the 2-acrylamido-2-methyl-1-propanesulfonic acid/11-methacrylamidoundecanoic acid (AMPS/MAU) copolymer, which is hydrophobic in acidic to neutral solution and hydrophilic in basic solution. Titanium dioxide subjected to surface treatment was treated with the AMPS/MAU copolymer showed a high pH-responsiveness that was similar to that of the polymer. A W/O-type sunscreen containing the pH-responsive titanium dioxide showed a high water resistance as well as a high washability with regular soap.
Keywords: Detergent-washable, pH-responsive polymer, pH-responsive powder, sun care product, water-resistant 相似文献
It is generally well known that the surface of an inorganic UV-protective powder used in a sunscreen formula is treated with a fatty acid or other hydrophobic chemicals to obtain a high water resistance. Due to the resulting strongly hydrophobic surface, the treatment has a clear drawback in that it allows the sunscreen to leave its base components on the skin after washing with regular soap. Therefore, in this study to develop an intelligent sunscreen formula that has a high water resistance and can be washed away easily with regular soap, we focused on a pH-responsive polymer as the surface-treatment agent for a UV-protective powder. Numerous experiments led to the synthesis of the 2-acrylamido-2-methyl-1-propanesulfonic acid/11-methacrylamidoundecanoic acid (AMPS/MAU) copolymer, which is hydrophobic in acidic to neutral solution and hydrophilic in basic solution. Titanium dioxide subjected to surface treatment was treated with the AMPS/MAU copolymer showed a high pH-responsiveness that was similar to that of the polymer. A W/O-type sunscreen containing the pH-responsive titanium dioxide showed a high water resistance as well as a high washability with regular soap.
Keywords: Detergent-washable, pH-responsive polymer, pH-responsive powder, sun care product, water-resistant 相似文献
68.
AT Bender AM Silverstein DR Demady KC Kanelakis S Noguchi WB Pratt Y Osawa 《Canadian Metallurgical Quarterly》1999,274(3):1472-1478
It is established that the multiprotein heat shock protein 90 (hsp90)-based chaperone system acts on the ligand binding domain of the glucocorticoid receptor (GR) to form a GR.hsp90 heterocomplex and to convert the receptor ligand binding domain to the steroid-binding state. Treatment of cells with the hsp90 inhibitor geldanamycin inactivates steroid binding activity and increases the rate of GR turnover. We show here that a portion of neuronal nitric-oxide synthase (nNOS) exists as a molybdate-stabilized nNOS. hsp90 heterocomplex in the cytosolic fraction of human embryonic kidney 293 cells stably transfected with rat nNOS. Treatment of human embryonic kidney 293 cells with geldanamycin both decreases nNOS catalytic activity and increases the rate of nNOS turnover. Similarly, geldanamycin treatment of nNOS-expressing Sf9 cells partially inhibits nNOS activation by exogenous heme. Like the GR, purified heme-free apo-nNOS is activated by the DE52-retained fraction of rabbit reticulocyte lysate, which also assembles nNOS. hsp90 heterocomplexes. However, in contrast to the GR, heterocomplex assembly with hsp90 is not required for increased heme binding and nNOS activation in this cell-free system. We propose that, in vivo, where access by free heme is limited, the complete hsp90-based chaperone machinery is required for sustained opening of the heme binding cleft and nNOS activation, but in the heme-containing cell-free nNOS-activating system transient opening of the heme binding cleft without hsp90 is sufficient to facilitate heme binding. 相似文献
69.
Role of Tannin-Binding Salivary Proteins and Tannase-Producing Bacteria in the Acclimation of the Japanese Wood Mouse to Acorn Tannins 总被引:1,自引:0,他引:1
We studied the defense mechanisms against the negative effects of tannins in acorns by using the Japanese wood mouse (Apodemus speciosus) and acorns of a Japanese deciduous oak Quercus crispula, which contain 9.9% tannins on a dry weight basis. For the experiment, we allocated 26 wood mice into two groups: acclimated (N = 12) and nonacclimated (N = 14). Mice in the nonacclimated group were fed only acorns for 10 d after 4 wk of receiving a tannin-free diet. In contrast, mice in the acclimated group received ca. 3 g acorns daily in addition to the tannin-free diet for the first 4 wk, then they were fed only acorns for 10 d. Body weight, food intake, and digestibility were monitored. In addition, the amount of salivary proline-rich proteins (PRPs) and abundance of tannase-producing bacteria (TPB) in the feces of mice were measured. Of the 14 mice in the nonacclimated group, 8 died, whereas only 1 of the 12 in the acclimated group died. During the first 5 d of feeding acorns only, mice in the nonacclimated group lost, on average, 17.5% of their body mass, while those in the acclimated group lost only 2.5%. Food intake, dry matter digestibility, and nitrogen digestibility were higher in the acclimated group than in the nonacclimated group. The results indicate that wood mice can mitigate the negative effects of tannins by acclimation. Path analysis revealed that increased secretion of PRPs and abundance of Lactobacillus type of TPB might explain the acclimation to tannins. 相似文献
70.