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61.
Ana Cuesta Amelia Martí nez-Alonso Juan M. D. Tasc n 《Fullerenes, Nanotubes and Carbon Nanostructures》1997,5(5):1075-1081
Fullerene reactivity in an oxygen plasma was measured and compared with those determined under the same conditions for a comprehensive set of 50 carbon materials. The possible reasons for the high plasma reactivity of the fullerene sample in an oxygen plasma are discussed. 相似文献
62.
63.
Abstract: Maintainability problems associated with traditional software systems are exacerbated in rule-based systems. The very nature of that approach — separation of control knowledge and data-driven execution — hampers maintenance. While there are widely accepted techniques for maintaining conventional software, the same is not true for rule-based systems. In most situations, both a knowledge engineer and a domain expert are necessary to update the rules of a rule-based system. This paper presents, first, an overview of the software engineering techniques and object-oriented methods used in maintaining rule-based systems. It then discusses alternate paradigms for expert system development. The benefits of using case-based reasoning (from the maintenance point of view) are illustrated through the implementation of a case-based scheduler. The main value of the scheduler is that its knowledge base can be modified by the expert without the assistance of a knowledge engineer. Since changes in application requirements can be given directly to the system by the expert, the effort of maintaining the knowledge base is greatly reduced. 相似文献
64.
65.
Vincenzo Augelli Teresa Ligonzo Roberto Murri Luigi Schiavulli 《Thin solid films》1989,170(2):163-170
Hydrogenated and chlorinated silicon films were used to deposit Schottky barrier solar cells. Photovoltaic characterization, together with the results of electronic transport measurements, led to the conclusion that the presence of chlorine is detrimental to the properties of this kind of device. 相似文献
66.
EPON体系结构及应用分析 总被引:2,自引:2,他引:0
通过对EPON的体系结构、特点和应用优势、发展现状、关键技术、应用、技术难点的分析,可以看出,随着数据业务陕速增长,EPON将成为未来全光网中最佳的第一英里的解决方案. 相似文献
67.
Naiara Azurmendi Iñaki Caro Amador C. Caballero Teresa Jardiel Marina Villegas 《Journal of the American Ceramic Society》2006,89(4):1232-1236
Bismuth titanate-based ceramics, pure and doped with 5 mol% WO3 , were prepared by reaction-sintering using a microwave oven. High densities, ≥96% of theoretical density were achieved with very short thermal treatments, with soaking time ranging from 5 to 15 min. Relatively small platelet-like grains were formed, and microstructure seemed not to be strongly affected by doping nor soaking time. Electrical measurements were performed and, as expected, a decrease of electrical conductivity was observed in WO3 -doped materials. The results of reaction-sintered samples, both conventional as well as microwave sintered, are compared with those of samples prepared with previously calcined powders and sintered using microwaves as well as a conventional electric furnace. 相似文献
68.
Juan Carlos Benítez Carlos A. Giúdice Vicente J. D. Rascio 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1985,35(8):387-394
This paper discusses the bioactivity of antifouling paints based on organotin toxicants, such as tributyltin fluoride (TBTF) and triphenyltin fluoride (TPTF). These compounds were used alone or mixed as the main toxicant in formulations. The use of TPTF or mixtures of TPTF and TBTF, with vinyl binders, led to paints with satisfactory bioactivity during a 24 months immersion period. With the same binders, TBTF alone provided only 12 months of antifouling protection. The correlation coefficients calculated from the fouling attachment values and the rosin content in the binder showed that the bioactivity of the tested formulations depended on the solubility of the toxicant in sea water and on the composition and solubility of the binders. 相似文献
69.
Transport problems typically involve at least two types of constraints, on income and on time. Therefore, the indirect utility
function depends either on the income available after having subtracted the cost of the discrete alternative and on the free
time left after having worked and travelled by each competing option. In the typical linear-in-the-attributes and in-the-parameters
specification, that represents the first grade approximation of the indirect utility function, the effect of income and time
constraints cancel out and only the cost and time of the alternatives matter in the comparison between them. From a microeconomic
point of view this is equivalent to assume that income and time effects could be disregarded; which is not always the case.
To account for these effects the utility function should include second order attributes; however, in non-linear utility functions
it may not be easy to distinguish among several effects that could be relevant: direct preferences for good and leisure, and
simple interactions between attributes other than income and time effects. This paper analyses these effects from a theoretical
point of view focusing on the possible confounding problem in detecting income and time effects. We use a dataset collected
for a modal choice context and containing both revealed and stated preference data, and estimate several NL models examining
the effect of the different second-order terms on detecting income and time effects. We compared specifications including
square cost and time attributes, interactions between time and cost, cost divided by the income available to be spent on free
time, and time multiplied by free time. Our results confirm the strong effect of direct preferences for goods and leisure
time on choice, and the potential confounding effect between quadratic attributes and other non-linear omitted terms. Finally,
we also found that care should be taken in highlighting income and time effects using mixed data sources, since confounding
effects can occur when non-linearities are accounted for in both data sets. 相似文献
70.
Eva M. Valero Juan L. Nieves Sérgio M. C. Nascimento Kinjiro Amano David H. Foster 《Color research and application》2007,32(5):352-360
Many spectral‐recovery methods using RGB digital cameras assume the underlying smoothness of illuminant and reflectance spectra, and apply low‐dimensional linear models. The aim of the present work was to test whether a direct‐mapping method could be used instead of a linear‐models approach to recover spectral radiances and reflectances from natural scenes with an RGB digital camera and colored filters. In computer simulations, a conventional RGB digital camera with up to three colored filters was used to image scenes drawn from a hyperspectral image database. Three measures were used to evaluate recovery with the direct‐mapping method: goodness‐of‐fit, root‐mean‐square error, and a color‐difference metric. It was found that with two and three filters both spectral radiances and reflectances could be recovered sufficiently accurately for many practical applications. With little increase in computational complexity, an RGB camera and a few colored filters can provide significantly better recovery of natural scenes than an RGB camera alone. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 352–360, 2007 相似文献