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71.
Masatoshi Takahashi Masafumi Kikuchi Yukyo Takada 《Metals and Materials International》2011,17(1):175-179
The purpose of this study was to evaluate the corrosion resistance of experimental Ti-Ag alloys used as dental materials.
An elution test and a rest-potential measurement of alloys with 5–30 mass.% Ag were performed in a 1 % lactic acid solution.
The amount of Ti ions released from the α phase of the Ti-Ag alloys decreased as the Ag concentration increased. TiAg present
in the alloys dissolved preferentially, but Ti2Ag did not. The rest potentials of the Ti-Ag alloys were significantly higher than that of pure titanium. The elution test
and the rest-potential measurement revealed that the Ti-Ag alloys, which formed a single α-titanium structure or contained
a titanium and Ti2Ag, had excellent corrosion resistance that was comparable or superior to that of pure titanium. 相似文献
72.
The (240)Pu/(239)Pu atom ratios in seawater samples on the East China Sea continental shelf were measured. These ratios for surface and bottom waters had no significant difference. They were significantly higher than the average global fallout ratio of 0.18. It was proposed that the oceanic currents are accounted for delivery of close-in Pu from the Pacific Proving Grounds (PPG) to the studied areas. The contribution of the PPG close-in fallout was calculated to be 40 % on average. The (240)Pu/(239)Pu atom ratios should provide useful background data before the expected expansion of nuclear power capacity in East and South Asian countries and for distinguishing future sources of Pu. 相似文献
73.
Photodegradation of incombustible polymer materials [high-density (HD) and low-density (LD) polyethylene (PE) containing 0.5 to 2.0 phr of decabromodiphenyl ether (DBDE) or tetrabromobisphenol A (TBA) as a flame retardant] were studied using an Okazaki Large Spectrograph (OLS). Samples were irradiated in air at 23°C with monochromatic light of wavelengths at 260, 280, 300, 320, 340, and 360 nm. Ultraviolet and Fourier transform infrared (FTIR) spectra were taken to estimate the chemical changes caused by photoirradiation. Molecular weight change was followed by gel permeation chromatography (GPC) measurements. It was found that the photostability of PE samples was reduced by the addition of flame retardants. The threshold wavelengths of photodegradation are 320 nm and 360 nm for PE–TBA samples and PE–DBDE samples, respectively. Main-chain scission is favored when the irradiation was carried out with the light of wavelength 300 nm for HDPE–DBDE and HDPE–TBA samples. The most effective irradiation wavelengths for crosslinking are found to be 300 nm and 280 nm for LDPE–DBDE and LDPE–TBA samples, respectively. 1995 John Wiley & Sons, Inc. 相似文献
74.
Masatoshi Nakamura Takenao Sugi Akio Ikeda Hiroshi Shibasaki 《International Journal of Adaptive Control and Signal Processing》2002,16(1):25-37
In view of the fact that the visual EEG interpretation could be a subjective task and may vary among the electroencephalographers, the main objective of this study was to develop an automatic EEG interpretation system which is adaptable to each electroencephalographer. The system adapted to each electroencephalographer would bring a close automatic EEG interpretation to that done by the electroencephalographer's visual interpretation. The adaptable automatic EEG interpretation was accomplished by using the constructive neural network with forgetting factor. The artificial neural network was constructed so as to give the integrative interpretation of the EEG based on the intermediate judgment of 13 items that characterized the visual interpretation. The developed method was evaluated based on the visually inspected EEG data of 37 patients by electroencephalographer‐A and the data of 20 patients by electroencephalographer‐B. The adapted ANN showed good agreement with each electroencephalographer's visual inspection. The proposed automatic EEG interpretation by use of the ANN can be a powerful assistant tool for individual electroencephalographers for their EEG interpretation. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
75.
The thermally initiated emulsion copolymerization of styrene (ST) and methyl methacrylate (MMA) was carried out in the absence of conventional initiators. The hydroperoxide (HPO) concentration in the monomers, sodium dodecyl sulfate (SDS), deionized water, and the formulation of those for emulsion copolymerization were measured. The HPO concentration in ST and MMA increased with the storage time, and were considered to be the major sources of HPO. The thermal decomposition of hydroperoxide in monomers, the thermal initiation of ST by Mayo mechanism, and the complex formation between SDS and the monomers were proposed to be three main sources of the radical generation. It was confirmed that new polymer particles were generated throughout the polymerization process, and consequently resulted in a broader distribution of polymer particle size, compared with that for conventional emulsion polymerization. Approximately 80 wt % of monomer conversion was obtained in the presence of SDS at 373 K in 24 h. The initiation rate of the 30 wt % monomer charge was faster than those of 10 wt % and 20 wt % monomer charge. The latex instability at higher solid content was improved by adding electrolyte to promote the electrostatic repulsion force between the polymer particles. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 455–467, 2002; DOI 10.1002/app.2343 相似文献
76.
In order to know whether nitrogen dioxide, an environmental and endogenous free radical toxin, can participate in the formation
of atherosclerotic lesions, damage to low-density lipoprotein (LDL) by nitrogen dioxide and uptake of the damaged LDL by macrophages
were investigated. A solution of LDL at pH 7.5 was exposed to an atmosphere of nitrogen dioxide (70 ppm) in air at 37°C for
5 or 10 h. Lipid oxidation was induced by the exposure as assessed by the formation of thiobarbituric acid reactive substances.
Apolipoprotein B was covalently cross-linked via nondisulfide bonds. Fluorescence analysis showed that tryptophan residues
were extensively decreased, and amino acid analysis indicated that the contents of histidine, lysine, and tyrosine residues
were decreased by 30–40, 10–20, and 20–30%, respectively. Binding of LDL to thioglycolate-induced mouse peritoneal macrophages
was markedly increased by the exposure as observed by the binding of mouse erythrocytes coated with LDL. The activity of LDL
to convert macrophages into lipid-laden foam cells was also increased by the exposure. Modification of lysine residues of
apo B with lipid oxidation products formed by the exposure may be responsible for the uptake by macrophages. The results suggest
the possibility that exposure of LDLin vivo to nitrogen dioxide participates in the formation of atherosclerotic lesions. 相似文献
77.
Experiment and numerical simulation of double-layered RC plates under impact loadings 总被引:1,自引:0,他引:1
Tetsuo Shirai Atsushi Kambayashi Tomonori Ohno Hajime Taniguchi Masatoshi Ueda Nobutaka Ishikawa 《Nuclear Engineering and Design》1997,176(3)
This paper is to investigate and to propose a method to improve the impact resistance of reinforced concrete (RC) plates against projectile impact, and the damage of double-layered RC plates is examined experimentally and simulated analytically. In tests, a projectile launching apparatus, which is a 40 mm smooth-bore airgun, was used. Based on experimental results, numerical simulations with the DYNA-3D code, which takes account of the dynamic constitutive law of concrete, were done to find the applicability of the present computer code to the analysis of double-layered RC plates under high-speed impact loadings. In this study, the impact resistance of concrete plate is defined as the degree of local damage. In both experiments and numerical simulations, the effect of double-layering on the impact resistance is discussed. 相似文献
78.
Takao Yamamoto Shuichi Okuda Masatoshi Fujishiro 《Journal of Nuclear Materials》1988,160(2-3):247-252
A thin titanium layer with uniformly absorbed tritium (T/Ti ˜1.0) was bombarded by 390 keV D3+ ions (130 keV per deuteron). Bombardment was performed at low (111 K) and room temperatures up to fluences of 5.9 × 1018 D/cm2 and 3.0 × 1018 D/cm2, respectively. Depth profiles of tritium up to a depth of 0.8 mg/cm2 (˜1.8 μm) were measured and the change of the profile with fluence was investigated by means of the T(d, )n nuclear reaction. At both of the temperatures, a dip was formed on the depth profile of tritium at the depth around the projected range, indicating that the deuteron bombardment induced the migration of tritium against the concentration gradient. At the low temperature, the dip showed a gradual growth with fluence and saturation of the growth at the higher fluences, which could not be described by the existing model for isotope mixing. The spectrum of protons from the D(d, p)T reaction obtained in the same measurement suggested that the release of deuterium suddenly started at the final stage of the present bombardment. The dip formed at room temperature was larger than that at the low temperature. The migration of tritium induced by the bombardment is discussed on the basis of the experimental results obtained. 相似文献
79.
Small-angle X-ray scattering (SAXS) patterns have been calculated based on a structure model, which consisted of the bundles of long-period structures. The proposed model has produced various scattering patterns of polymers, such as the equatorial, layer line, four-spot, droplet-shaped and triangular scattering. The 0.5th order scattering has arisen when the disorder in or between the long-period structures was large even though the structure did not have the periodicity directly related to the scattering maximum. A slight decrease in the disorder due to slip between the long-period structures has accounted for the sudden change of the SAXS pattern of a poly(ethylene terephthalate) fiber from the four-spot to the layer line scattering which was caused by a slight tensile deformation. 相似文献
80.
Akira Matsumoto Takayuki Nakagawa Masatoshi Sato Yasunori Kimura Kenji Nishida Atsuhiro Goto 《New Generation Computing》1991,9(2):149-169
The parallel inference machine (PIM) is now being developed at ICOT. It consists of a dozen or more clusters, each of which
is a tightly coupled multiprocessor (comprising about eight processing elements) with shared global memory and a common bus.
Kernel language 1 (KL1), a parallel logic programming language based on Guarded Horn Clauses (GHC), is executed on each PIM
cluster.
This paper describes the memory access characteristics in KL1 parallel execution and a locally parallel cache mechanism with
hardware lock. The most important issue of locally parallel cache design is how to reduce common bus traffic. A write-back
cache protocol having five cache states specially optimized for KL1 execution on each PIM cluster is described. We introduced
new software controlled memory access commands, named DW, ER, and RP. A hardware lock mechanism is attached to the cache on
each processor. This lock mechanism enables efficient word-by-word locking, reducing common bus traffic by using the cache
states. 相似文献