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81.
Osami Yanagisawa Mitsuru Izumi Wei-Zhi Hu Kenji Nakanishi Hideo Nojima 《Journal of Superconductivity》1999,12(1):307-310
The magnetic behavior of the distorted perovskite manganese, Pr0.65Ca0.35MnO3 was studied by X-band electron spin resonance for powder samples. We observed the onset of the charge-ordered state at T
CO215 K, the antiferromagnetic transition with the peak of the ESR linewidth, H
p–p
at T
AF180 K and the canted antiferromagnetic transition at T
CAF125 K associated with the abrupt increase of both the effective magnetization and H
p–p
. Below 90 K, the absorption intensity profile becomes weakened with decreasing temperature suggesting the existence of some kind of magnetic disorder below 90 K, which is responsible for a part of evidence of the existence of the spin-glass state as has been proposed by Yoshizawa et al., Phys. Rev. B
52, 1689 (1996). 相似文献
82.
Yasunari Nagaki Satoru Itabashi Hideo Mitsui Mototaka Sone 《Electrical Engineering in Japan》1994,114(3):23-32
It has been proposed that vapor-mist dielectrics in which mixing liquid droplets such as tetrachloroethlene in a gas have the ability of increasing flashover, impulse voltage, and of suppressing partial discharge. Vapor-mist methods have been performed on other materials and the effect of the mist can also be obtained on benzene, hexane, and even water as general materials. Although these studies have been carried out, neither the discharge mechanism on vapor-mist nor the reason for the increase of the discharge voltage is understood fully because the mist is of various sizes. On the other hand, agglomeration of water molecules can be studied with the FR-IR method, and are classified into monomer, dimer, trimer (including polymer). Water gives mist stats which are significant in discussing effects. This paper describes states of water mist and their effect under nonuniform field with positive and negative polarities. Water mist in vapor exists as dimer and trimer, and their amount decreases with the reduction of temperature. These mists have no effect on discharge suppression. However, when the mists are formed by space charges, the inception voltage is increased by these mists in the negative polarity. 相似文献
83.
Takeshi Naito Hideo Ueda Masao Kikuchi 《Metallurgical and Materials Transactions A》1984,15(7):1431-1436
The characteristic fatigue behavior of carburized and quenched steel with internal oxides and non-martensitic microstructure near the surface was presented through rotating bending fatigue test. The S-N diagram revealed two knees and the specimens continued to fail over 107 stress cycles. The fatigue limit could not be obtained even at 108 stress cycles. The test results were compared to those for the specimens without surface structure anomalies to show the effect of structure anomalies on the fatigue behavior of carburized steel. 相似文献
84.
The mechanical properties of Fe-13 wt% Cr-2 wt% Mo-2.5 wt% Ti alloy were examined by tensile tests with respect to its fracture mechanism. In order to improve the properties, 1 wt% Nb was added and its effects were examined. In the temperature range, room temperature to 500° C, the fracture characteristics of the alloys are mainly governed by the characteristics of the x-phase precipitation. Fracture elongation is a function of (C/r)1/2 where C is the radius of the x-phase and r is its mean spacing. 1 wt% Nb addition is an effective method for improving the ductility without a decrease in the strength of the alloy. 相似文献
85.
The method has been developed to improve the bitumen product which incorporates an evaporator concentrate from a BWR, with respect to the swelling and leaching. The leachability of the product has been measured by the method recommended by the IAEA. The swelling of the product is successfully prevented by the addition of calcium chloride. The specimen containing the waste up to Wa/B (Weight ratio of Na2SO4 + CaCl2 and bitumen) = 60:40 shows no pronounced swelling, when it is immersed in water. The cumulative fractions of 137Cs and 60Co leached from a specimen which does not contain CaCl2 are 0.65 and 0.2 at the leaching time of 30 days. On the hand, the corresponding value at 100 days for the specimen with calcium chloride addition is 5 × 10?4 for 137Cs and 1 × 10?4 for 60Co. The coating of the specimen surface with a fresh bitumen (5 mm thickness) reduces the leachability further. These results indicate that this method is effective to improve the bitumen product incorporating BWR's evaporator concentrate. 相似文献
86.
87.
Koizumi H Yamamoto T Maki A Yamashita Y Sato H Kawaguchi H Ichikawa N 《Applied optics》2003,42(16):3054-3062
We will briefly review the present status of optical topography and then discuss the method of improving practicality, i.e., the signal-to-noise (S/N) ratio and the spatial resolution in observations of higher-order brain functions. The optimum wavelength pair improved the S/N ratio sixfold for deoxyhemoglobin, and new configurations of light irradiation and detection positions doubled the spatial resolution. We also report on developing application fields of optical topography. This modality will bridge the gap between natural sciences, neuroscience, and pedagogy, and show actual real-time brain activity. 相似文献
88.
For the visualization of phase objects by use of a differentiation filter, the phase variation is changed into the intensity variation by differentiation, and then the differentiated image is integrated. In the method used in practice, the differentiated image has been recorded on a film, and then integrated by use of a filter. In this paper, however, the image differentiated by means of a filter is entered into a computer using a CCD camera and then integrated. As a result, the method provides rapid on-line processing. We have performed computer simulations and a detailed analysis of the differentiation filter and also provide the experimental results of three-dimensional image visualization. 相似文献
89.
This article reviews our approach to render 12CaO · 7Al2O3 (C12A7) electronically active using a new concept of ‘active anion manipulation’, where nanostructures embedded within the
C12A7 crystal lattice are intentionally utilized to generate chemically unstable (‘water-free active’) anions. Anionic active
oxygen radicals, O− and O2−, are formed efficiently in C12A7 cages under high oxygen activity conditions. The configuration and dynamics of O2− in cages are revealed by a combination of continuous-wave and pulsed electron paramagnetic resonance (EPR). It is demonstrated
that metal-loaded C12A7 is a promising oxidation catalyst for syngas (CO + H2) formation from methane. Furthermore, the O− ion, the strongest oxidant among active oxygen species, can be extracted from the cage into an external vacuum by applying
an electric field with thermal assistance, generating a high-density O− beam in the order of μA cm−2. In contrast, heat treatment of C12A7 in a hydrogen atmosphere forms H− ions in the cages. The resultant C12A7:H− exhibits a persistent insulator-conductor conversion upon ultraviolet-light or electron-beam irradiation. The irradiation-induced
conversion mechanism is examined by first-principle theoretical calculations. Furthermore, the presence of a severely reducing
environment causes the complete substitution of electrons for anions in the cages. The resulting C12A7:e−, which exhibits excellent stability and an electrical conductivity greater than 100 S cm−1, is regarded as an ‘electride’, an ionic compound in which electrons serve as anions. The C12A7 electride exhibits a high
potential for applications involving cold cathode and thermal field electron emissions due to its small work function. Electride
fabrication methods suitable for large-scale production via melt processing are described. It is also demonstrated that proton
or inert gas ion implantations into C12A7 thin films at elevated temperatures are effective for both H− and electron doping. 相似文献
90.
The problem of reducing the pulsating torque in current source inverter induction motor systems is investigated. Two typical approaches presented in recent publications are analyzed by making clear 1) the correlation among the current harmonics and the torque harmonics, and 2) the conceptual contradiction existing between these two approaches. By synthesizing the analyzed results, fundamental principles for treating the current harmonics and torque harmonics are established. In addition, the method for evaluating the degree of torque ripple is described, along with a proposed criterion for torque ripple content. By applying this criterion to these two approaches, objective estimates of degree of torque pulsations, which were unfeasible so far, are now made possible. 相似文献