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排序方式: 共有1110条查询结果,搜索用时 15 毫秒
991.
液化场地堤坝地震响应的自适应步长法数值模拟 总被引:1,自引:0,他引:1
土体在地震液化过程中表现为较强的材料非线性,此时动力数值分析中时间步长过大必然导致较大的误差。本文在水土耦合弹塑性有限元法和Newmark时域离散法的显式动力液化数值分析平台上,引入时域离散后验误差评估方法,并基于误差评估结果进行了时间步长的自适应调整,建立了基于自适应时间步长的液化动力数值分析方法,并将此方法应用于液化场地堤坝的地震响应数值模拟。通过分析堤坝算例,对比了自适应时间步长法和固定时间步长法计算的堤坝变形、超孔隙水压力比和平均相对误差等的变化规律。结果表明自适应时间步长法在土体动力液化显式数值分析中可以获得较高的计算精度,同时也可以提高计算效率、节省计算时间。 相似文献
992.
This paper describes Macro-informatics of cognition that is the guideline for mathematical formulation of macroscopic feature. The macroscopic feature emerges from the total of shape elements, and the feature is important in the styling design. The mathematical formulation of macroscopic feature is difficult using conventional microscopic shape information such as dimension and curvature. In this paper, for formulation of macroscopic feature, the importance of “condition” that is various physical elements in the circumstance is mentioned. Moreover, this paper describes the mathematical formulation of macroscopic feature “complexity,” and its application for design. The formulation consists of curvature integration and multi-resolution representation. In application, shape generation method based on a genetic algorithm is introduced. 相似文献
993.
Satoshi Matsuoka 《Electronic Notes in Theoretical Computer Science》2001,50(2):130-144
First we present a proof nets system with eight additional rewrite rules, which concerns ordering of introductions of exponential-links and are only applied to normal forms of proof nets in the usual sense. We show that the reduction relation generated by these eight rewrite rules is strong normalizing and confluent. Second we propose an simply judged equality on intuitionistic proof nets based on the notion of the main path of an intuitionistic proof net. The notion is an analogue of Böhm-trees in λ-calculus. 相似文献
994.
Y Okano M Akizuki H Kondo S Kawai Y Suzuki T Takeuchi Y Matsuoka Y Kawaguchi S Kashiwazaki 《Canadian Metallurgical Quarterly》1997,37(3):467-475
To characterize the American College of Rheumatology core set of disease activity measures for rheumatoid arthritis (RA) clinical trials (ACR core set measures) and the ACR definition of improvement of RA (ACR improvement definition), we studied 42 Japanese patients with active RA who were treated with DMARDs including mizoribine. Each patient's disease activity was assessed at the time of enrollment to the study and after 24 weeks using the ACR core set measures as well as the physical global assessment through the conventional measures. Twenty-five (60%) patients were discerned as showing improved by physicians through the conventional measures. This decision appeared to be based on improvement in Lansbury activity index (LAI) and C-reactive protein (CRP) value. Twelve of the 25 "improved" patients satisfied the ACR improvement definition. The 12 patients showed significant improvement in "outcome" measures including patients assessments of pain, disease activity, and physical function, compared to the 30 patients not satisfying the ACR definition. However, no significant differences were observed between these two groups in "process" measures including LAI, tender joint count, swallen joint count, or CRP value. In conclusion, the ACR core set measures including both process and outcome measures have potential to reflect clinical important changes on "real life" of patients with RA. 相似文献
995.
Isao Mochida Hideichi Matsuoka Hiroshi Fujitsu Yozo Korai Kenjiro Takeshita 《Carbon》1981,19(3):213-216
The carbonization properties of pyrene hydrogenated by Birch reduction to a variable extent were studied at 600°C under atmospheric pressure, in order to examine the influence of partial hydrogenation on the carbonization reactivity. Pyrene, which did not yield any coke, produced coke with flow texture after partial hydrogenation. Carbon yield of partially hydrogenated pyrene sharply depended on the hydrogenation extent. The intermediate stage of the carbonization pursued by hot-stage microscopy followed the steps of nucleation, growth and coalescence of anisotropic sphere. Considerable fluidity was observed at the final stage of mesophase development prior to the complete solidification where the benzene insoluble content exceeded 90%. The carbonization mechanism was discussed from the view of the polymerization of hydrogenated pyrene in relation with its structure. 相似文献
996.
Yukio Mizutani Seishiro Matsuoka Masatoshi Iwasaki Yoshimichi Miyazaki 《应用聚合物科学杂志》1973,17(12):3651-3660
In order to prepare fine powdery and crosslinked copolymer as a foaming agent and a modifier for polypropylene, the following processes were investigated: (1) polymerization of monoalkyl maleate–styrene–divinylbenzene; (2) polymerization of monoalkyl maleate–maleic anhydride–styrene–divinylbenzene; (3) polymerization of maleic anhydride–styrene–divinylbenzene and esterification of the copolymer with methanol, and (4) polymerization of maleic anhydride–styrene–divinylbenzene in the presence of methanol. The thermal treatment of copolymer thus obtained and the foaming ability for polypropylene were then investigated. 相似文献
997.
The development of visible light-responsive TiO2 (Vis-TiO2) thin films has been achieved by applying a radio-frequency magnetron sputtering deposition (RF-MS) method. Pt-loaded Vis-TiO2 thin films act as photocatalysts to decompose water involving sacrificial reagent such as methanol or silver nitrate even
under visible light (λ ≧ 420 nm) irradiation. It was also found that Pt-loaded Vis-TiO2 thin films decompose pure water into H2 and O2 stoichiometrically under light irradiation of wavelengths longer than 390 nm. Vis-TiO2 thin films exhibit columnar structures perpendicular to the substrate and a declined composition of the O/Ti ratio from the
surface (O/Ti = 2.00) to bottom (O/Ti = 1.93). This unique structure (anisotropic structure) of Vis-TiO2 can be considered an important factor in the modification of the electronic properties of Vis-TiO2 thin films, enabling the absorption of visible light. Furthermore, the effect of the Pt loadings on the photocatalytic activity
of the TiO2 thin films was investigated and the optimum Pt loading was determined to be 21 μ g/cm2 as Pt metal 相似文献
998.
Electrochemical characteristics of hydrogen storage alloys modified by electroless nickel coatings 总被引:1,自引:0,他引:1
K. Naito T. Matsunami K. Okuno M. Matsuoka C. Iwakura 《Journal of Applied Electrochemistry》1994,24(8):808-813
Multicomponent hydrogen storage alloy with the composition MmNi3.31Mn0.37Al0.28CO0.64 (Mm = misch metal consisting of 24.87% La, 52.56% Ce, 5.57% Pr, 16.86% Nd and 0.14% Sm) was used as a negative electrode material. To improve the performance of the negative electrode, the alloy particles were modified with various electroless Ni-P and Ni-B coatings. Electrochemical properties such as discharge capacity and high-rate dischargeability of the negative electrode were generally improved by the surface modifications. However, in the case of a Ni-P (10 wt % P) coating, the discharge capacity and high-rate dischargeability decreased with increasing thickness, due to the low hydrogen permeability and high electric resistivity of the coating. Consequently, both kinds of coating and their thickness are critical factors in determining the performance of such a negative electrode. 相似文献
999.
Photocatalytic decomposition of NO on titanium oxide thin film photocatalysts prepared by an ionized cluster beam technique 总被引:1,自引:0,他引:1
Masato Takeuchi Hiromi Yamashita Masaya Matsuoka Masakazu Anpo Takashi Hirao Nobuhisa Itoh Nobuya Iwamoto 《Catalysis Letters》2000,66(3):185-187
Transparent TiO2 thin film photocatalysts were prepared on transparent porous Vycor glass (PVG) by an ionized cluster beam (ICB) method. The
UV‐VIS absorption spectra of these films show specific interference fringes, indicating that uniform and transparent TiO2 thin films are formed. The results of XRD measurements indicate that these TiO2 thin films consist of both anatase and rutile structures. UV light (λ > 270 nm) irradiation of these TiO2 thin films in the presence of NO led to the photocatalytic decomposition of NO into N2, O2 and N2O. The reactivity of these TiO2 thin films for the photocatalytic decomposition of NO is strongly dependent on the film thickness, i.e., the thinner the
TiO2 thin films, the higher the reactivity.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
1000.
In situ synchrotron X-ray diffraction measurements of single-walled carbon nanotube and C60-peapod samples under high pressures up to 13 GPa and at high temperature were carried out. Anisotropical shrinkages of their bundle two-dimensional lattices by compression at room temperature were observed. It was found that the lattices recover original forms reversibly upon pressure release. It was also found that irreversible phase transformations occur by raising temperature at the highest pressure. The high pressure and high temperature treated samples were examined by X-ray diffraction, transmission electron microscope, and Raman measurements. It was indicated by transmission electron microscope observation that hexagonal diamond is able to be synthesized by high pressure and high temperature treatment of C60-peapods. 相似文献