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排序方式: 共有570条查询结果,搜索用时 46 毫秒
61.
F Nagawa K Ishiguro A Tsuboi T Yoshida A Ishikawa T Takemori AJ Otsuka H Sakano 《Canadian Metallurgical Quarterly》1998,18(1):655-663
We have studied the interaction between recombination signal sequences (RSSs) and protein products of the truncated forms of recombination-activating genes (RAG) by gel mobility shift, DNase I footprinting, and methylation interference assays. Methylation interference with dimethyl sulfate demonstrated that binding was blocked by methylation in the nonamer at the second-position G residue in the bottom strand and at the sixth- and seventh-position A residues in the top strand. DNase I footprinting experiments demonstrated that RAG1 alone, or even a RAG1 homeodomain peptide, gave footprint patterns very similar to those obtained with the RAG1-RAG2 complex. In the heptamer, partial methylation interference was observed at the sixth-position A residue in the bottom strand. In DNase I footprinting, the heptamer region was weakly protected in the bottom strand by RAG1. The effects of RSS mutations on RAG binding were evaluated by DNA footprinting. Comparison of the RAG-RSS footprint data with the published Hin model confirmed the notion that sequence-specific RSS-RAG interaction takes place primarily between the Hin domain of the RAG1 protein and adjacent major and minor grooves of the nonamer DNA. 相似文献
62.
63.
We report here on the first observation of hysteresis in the asymmetrical tuning curve of a semiconductor laser operating as a resonant-type amplifier. This bistable amplification resulting from a nonlinear resonance phenomenon is caused by the dependence of the refractive index on the injected carrier density. 相似文献
64.
Effect of cyclic deformation on the pseudoelasticity characteristics of Ti-Ni alloys 总被引:5,自引:0,他引:5
Change in the pseudoelasticity characteristics of Ti-Ni alloys during tension cycling was investigated. The critical stress
for inducing martensites and the hysteresis of a stress-strain curve decreased with increasing number of cyclic loading, while
the permanent elongation increased. The degree of the change in these values showed a strong dependence on the maximum applied
stress during stress-induced martensitic transformation. However, no change was induced by cyclic elastic deformation even
though high stress was applied. It was also found that the stabilization of the pseudoelasticity characteristics during cyclic
loading was established using special thermomechanical treatments which are effective to raise the critical stress for slip.
Based on these results it is concluded that the cause for the effect of cyclic deformation is the generation of dislocations
in the martensitic phase. 相似文献
65.
Carbonaceous spherules of mesophase were examined by transmission electron microscopy (TEM) and X-ray diffraction to precisely
clarify its structure. A series of thin sections were cut from a single spherule with a microtome, and the three-dimensional
lamellar structure of the spherule investigated. From 002 dark-field images and selected area electron diffractions (SAD),
it was observed that the spherule was of the Brooks-Taylor type, with the lamellae being parallel even at the poles of the
spherule. Structural changes within the spherule was studied following carbonization and graphitization. The structure of
the resultant coke was essentially that of spherule of mesophase. Size of the lamellae increased as well as. The number of
stacking lamellae also increased, but a rapid increase was not seen. The spherules of mesophase show a high degree of homogeneity
and an excellent degree of graphitization. 相似文献
66.
A Kimura H Igarashi H Ushioda K Okuzumi H Kobayashi T Otsuka 《Canadian Metallurgical Quarterly》1993,67(3):223-230
Drug susceptibility of 430 Staphylococcus aureus strains isolated in 1991 from clinical specimens at all of the Japanese national university hospitals was evaluated in relationship with the epidemiological markers, namely, coagulase typing, and staphylococcal enterotoxins (SE) and toxic shock syndrome toxin 1 (TSST-1) production. There were five major methicillin-resistant Staphylococcus aureus (MRSA) groups in all the 252 MRSA strains: coagulase-type II-SEC + TSST-1- producing strains (II-SEC + TSST-1): 34.5%; coagulase-type II-no toxin-producing strains (II-): 15.4%; coagulase-type IV-SEA-producing strains (IV-SEA): 10.3%; coagulase-type II-SEA + SEC + TSST-1- producing strains (II-SEA + SEC + TSST-1): 8.7%; and coagulase-type III-no toxin-producing strains (III-): 7.1%. II-SEA + SEC + TSST-1 group was highly resistant to OFLX, whereas half of the other strain groups were sensitive to OFLX. Seventy-eight percent of the IV-SEA group was sensitive to FMOX, but there was no sensitive strain to FMOX in the II-SEA + SEC + TSST-1 group. More than 50% of the IV-SEA, III- and II-groups were sensitive to IPM, while the II-SEC + TSST-1 and II-SEA + SEC + TSST-1 groups were highly resistant to IPM. The III- and II-groups showed very good sensitivity to MINO, but the sensitivity to it of the II-SEA + SEC + TSST-1 group was very low. All of the strain groups were sensitive to ST except for the IV-SEA group. These results may provide useful information in the choice of antibacterial agents for MRSA infection. 相似文献
67.
68.
Fatty acid synthetase was isolated from guinea pig Harderian gland. This enzyme complex exhibited a unique character as compared with the fatty acid synthetase from the liver of the same animal. The former enzyme produced many odd-numbered and methyl-branched fatty acids in the presence of methylmalonyl-CoA. These fatty acids are characteristic components of the lipid secreted from this gland. The chemical structure of this lipid has been identified as 1-O-alkyl-2,3-diacylglycerol by previous work from this laboratory (Yamazaki, T., Seyama, Y., Otsuka, H., Ogawa, H., & Yamakawa, T. (1981) J. Biochem. 89, 683-691). Apparent Km values (5 X 10(-6) M) for acetyl-CoA and propionyl-CoA were the same, but the Vmax for propionyl-CoA was much higher than that for acetyl-CoA. The pI value of the fatty acid synthetase from Harderian gland was 5.3, and the molecular weight of the enzyme was 9 X 10(5) daltons. The beta-ketoacyl reductase had pro-S stereospecificity and the enoly reductase had pro-R stereospecificity for NADPH. The results presented in this paper indicate that the fatty acid synthetase from guinea pig Harderian gland can produce a set of fatty acids needed for the synthesis of the lipid secreted from this gland, and that the fatty acid synthetase has a characteristic organ specificity. 相似文献
69.
The production of hydrogen from water by reduced tin oxide has been examined under various experimental conditions. It has been concluded that the reactive species decomposing water is metallic tin. The coexistence of SnO2 with metallic tin enhances the rate of hydrogen production remarkably. The effect of SnO2 has been ascribed to the enlargement of surface area of tin metal by its dispersion on the surface of SnO2. Solid additives such as Pd, Pt, WO3, CuO and CaO showed a large promoting effect for hydrogen production. The effect of the additives may be explained by increase in the surface area of tin metal or by the spill-over of the activated water by additives onto the surface of SnO2 or tin metal. 相似文献
70.