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71.
An HIP compact of MA-processed powder having a nominal composition of Ti-48at.% Al was produced. The compact consisted of a large amount of TiAl(λ) and a small amount of Ti3Al (2), in a completely ultra-fine equiaxed grain structure. This two-phase compact showed typical superplastic deformation behaviour. A maximum elongation of 550% was obtained. A strain exponent, n = 2, and grain size exponent, p = 2, were determined from the results of a strain-rate-change test and a creep test at constant initial stress using samples having various grain sizes, respectively. The activation energy for creep, Qc at constant stress was calculated to be 350 kJ/mole. It is concluded that the superplastic deformation mechanism of the material under study is grain boundary sliding controlled by lattice diffusion in the TiAl phase. 相似文献
72.
Kanazawa T Atsumi M Mineo H Fukushima M Nishimura N Noda T Chiji H 《Journal of oleo science》2008,57(6):335-343
Potato starch is known to have a higher concentration of phosphate than other starches. The presence of phosphate groups in amylopectin results in resistance to digestion by amylase. Therefore, there is a possibility that potato starch is slowly digested, inducing a physiological effect similar to that of resistant starch and indigestible oligosaccharides. The amount of phosphate group in starch differs with potato cultivar. In the present study, we investigated the effects of gelatinized potato starch containing a high level of phosphorus on lipid metabolism in rats. For this purpose, we determined lipid levels in the serum and liver in rats fed two kinds of gelatinized potato starches with different phosphorus contents. Four groups of male Sprague-Dawley rats were fed a 60% sucrose diet (control) or one of three diets containing cornstarch (CS), Benimaru (BM) potato starch or Hokkaikogane (HK) potato starch. Fat pad weight was slightly decreased in the HK diet group compared with that in the other groups. Free fatty acids in serum were significantly lowered by dietary HK starch compared with control, and serum triglyceride in rats fed the HK diet was also decreased. In the BM and HK diet groups, triglyceride levels in the liver were decreased compared with that in the control and CS groups. As for hepatic total cholesterol level, there were no significant differences among three starch diet groups. Fecal bile acid excretion was greater in the two potato starch groups than in the control group. On the other hand, there were no significant differences in cecal short-chain fatty acid content or pH. Thus, we conclude that dietary gelatinized potato starch reduces free fatty acid and triglyceride in serum and hepatic triglyceride, but does not affect cecal fermentation. 相似文献
73.
Naoya Katayama 《时间序列分析杂志》2008,29(2):359-370
Abstract. The portmanteau statistic is based on the first m‐residual autocorrelations, and is used for diagnostic checks on the adequacy of fit of a model. In this article, we propose a modified portmanteau statistic with a correction term that allows for the use of small values of m for the chi‐squared test. For this modification, we take a different approach to that suggested by Ljung [Biometrika (1986), Vol. 73, pp. 725–30]. Their empirical behaviour is clarified using asymptotic theory. 相似文献
74.
Sun-Chan Jeong Ichiro Katayama Hirokane Kawakami Yutaka Watanabe Hironobu Ishiyama Nobuaki Imai Yoshikazu Hirayama Hiroari Miyatake Masao Sataka Satoru Okayasu Hiroyuki Sugai Shin-Ichi Ichikawa Katsuhisa Nishio Shinichi Mitsuoka Takamitsu Nakanoya Masahito Yahagi Takanori Hashimoto Kazunori Takada Mamoru Watanabe Tomoko Ishikawa Akihiro Iwase 《Journal of Phase Equilibria and Diffusion》2005,26(5):472-476
For the effective use of short-lived radioactive beams, soon to be available at the Tokai Radioactive Ion Accelerator Complex, the authors have developed a radiotracer method for diffusion studies in solids. The experimental test was performed by the measurement of the diffusion coefficients of Li in a sample of the compound βLiAl using an α-emitting radiotracer of 8Li (T1/2=0.84 s). It was found that the time-dependent yields of the α particles from the diffusing 8Li that was initially implanted in the sample could be used as a measure of the diffusivity of the tracer in a nondestructive way. The method was applied to measure the self-diffusion coefficients of Li in βLiGa, and for investigating how the Li diffusion in the Li ionic conductors is affected by the concentration of atomic defects (i.e., the existence of the atomic vacancies of Li and the defects in Ga sites that are replaced by Li). 相似文献
75.
Asako Yamamoto Lingli Yang Yasutaka Kuroda Jiao Guo Lanting Teng Daisuke Tsuruta Ichiro Katayama 《International journal of molecular sciences》2021,22(1)
As the outermost barrier of the body, skin is a major target of oxidative stress. In the brain, estrogen has been reported synthesized locally and protects neurons from oxidative stress. Here, we explored whether estrogen is also locally synthesized in the skin to protect from oxidative stress and whether aberrant local estrogen synthesis is involved in skin disorders. Enzymes and estrogen receptor expression in skin cells were examined first by quantitative real-time PCR and Western blot analyses. Interestingly, the estrogen synthesis enzyme was mainly localized in epidermal keratinocytes and estrogen receptors were mainly expressed in melanocytes among 13 kinds of cultured human skin cells. The most abundant estrogen synthesis enzyme expressed in the epidermis was 17β-hydroxysteroid dehydrogenase 1 (HSD17β1) localized in keratinocytes, and the most dominant estrogen receptor expressed in the epidermis was G protein-coupled estrogen receptor 1 (GPER1) in melanocytes. To investigate whether keratinocyte-derived estradiol could protect melanocytes from oxidative stress, cultured human primary epidermal melanocytes (HEMn-MPs) were treated with H2O2 in the presence or absence of 17β estradiol or co-cultured with HSD17β1 siRNA-transfected keratinocytes. Keratinocyte-derived estradiol exhibited protective effects against H2O2-induced cell death. Further, reduced expression of HSD17β1 in the epidermis of skin from vitiligo patients was observed compared to the skin from healthy donors or in the normal portions of the skin in vitiligo patients. Our results suggest a possible new target for interventions that may be used in combination with current therapies for patients with vitiligo. 相似文献
76.
To enhance chemical stability and suppress of aggregation of magnetite nanoparticles (MNPs), which are used as a support for thermoresponsive copolymer immobilization, silica coating of the MNPs is applied via the electrooxidation method. Although the resulting silica coated-MNPs also formed aggregates, the size distribution of the aggregate shifted to smaller size range. Because of that, the surface area available for copolymer immobilization increased approximately 6.7 times at maximum as compared with that of the uncoated MNPs. It contributed to the increase of the amount of the immobilized copolymer on the silica-coated MNPs, which is approximately four times larger than that on the uncoated MNPs. Fe3O4 dissolution test confirmed enhancement of chemical stability of MNPs. The thermoresponsive copolymer immobilized on the silica-coated MNPs shows the ability to recycle Cu(II) ion from Cu(II) containing solution by changing temperature with significantly shorter time than those in other thermoresponsive adsorbents in gel form. 相似文献
77.
Mamoru Ishida Takeo Uehara Toshio Arai Hideki Takeda Tadashi Yamaguchi Takeshi Taniguchi Tetsuya Katsumi Masayuki Kobayashi Hitoshi Ofune 《Intermetallics》2002,10(11-12)
The performance of MU/SC conversion sleeve produced by bulk metallic glass (Zr55Al10Ni5Cu30) was examined. A precision die-casting method was applied to improve size accuracy. The size accuracy of the conversion sleeve produced by the precision die-casting method was ±1 μm, and optical insertion loss (Li) was less than 0.3 dB for a standard value. The wear resistance of metallic glass is improved by surface oxidation treatment in air at 673 K. The MU/SC conversion sleeve produced from bulk metallic glass has superior characteristics for optical parts. 相似文献
78.
Micro biofabrication technologies have been developing aiming to fabricate 3D artificial organs, 3D scaffolds, and complex tissue structures. We are now developing a new inkjet bio-printing method via electrostatic phenomenon. The merits of the new method are of high resolution, and of ability to eject highly viscous liquid and media. In this paper, we attempted to apply the proposed method for precision printing cells and biomaterials. Living cells and scaffolds have successfully been printed and the biochemical characteristics have been investigated. A 3D cell structure which had a cavity to create blood vessels has also successfully fabricated by this method. 相似文献
79.
Based on literature sources and the author's own research, this article presents the current state of knowledge about composite coatings created by means of the plasma transfer method. The general characteristics of composite coatings and their strengthening mechanisms have been described. Methods of creating composite coatings by means of the plasma transfer method have also been discussed. 相似文献
80.
Koji Nishimoto Yoshihiro Okumoto Tomoki Harano Ken Atagi Hiroo Fujii Seiji Katayama 《Welding International》2013,27(10):734-743
Dissimilar metal joints of galvannealed steel and commercially available pure aluminium (A1050) sheets were produced by changing the laser power and the roller pressure by the laser pressure welding method. In this method, the YAG laser beam was irradiated into a flare groove made by these dissimilar metal sheets. In addition, the laser beam was scanned at various frequencies and patterns through the fθ lens using two-dimensional scanning mirrors. Then the sheets were pressed by the pressure rolls to be joined. The compound layers in the weld interface were observed by optical microscope, and the layer thicknesses were measured. The thicknesses were in the range of 7–20 μm. The mechanical properties of welded joints were evaluated by the tensile shear test and the peel test. In the tensile shear test, the strengths of the joints produced under the most welding conditions were so high that the fracture occurred through the base aluminium sheet. In the peel test of the specimens subjected to the laser beam of 1200–1400 W power under the roller pressure of 2.94 kN, the specimen fracture took place in the base aluminium sheet. Even if the compound layer was thick, high joint strength was obtained. In order to know the reason for such high strength of joints with thick compound layers and the joining mechanism, the compound layer was observed by the HR-TEM. The TEM observation results revealed that the main phase in the compound layer was the solid solution of Al + Zn. Moreover, the intermetallic compound was identified as FeAl, Fe2Al5, Fe4Al13, and Fe2Al5Zn0.4 phase by electron diffraction. The Fe3Zn10 (Γ phase) of Fe–Zn intermetallic compound was confirmed on a Fe base material. It is assumed that the joining areas were heated in a range of 782°C more than 665°C, a melting point of Al, by laser irradiation because the δlk phase aspect was not confirmed. Because the surfaces of A1050 and Zn plated layer were melted thinly, the layer was over 10 μm thicker. The reason for the production of high strength joints with the relatively thick intermetallic compound layer was attributed to the formation of (Al + Zn) phase with finely dispersed intermetallic compounds. 相似文献