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141.
Simon JM Comastri SA 《Journal of the Optical Society of America. A, Optics, image science, and vision》2004,21(8):1488-1495
In 1987 we published "Fringe localization depth" [Appl. Opt. 26, 5125 (1987)], where, with first principles, we generalized the van Cittert-Zernike theorem for two-beam amplitude-division interferometers illuminated by extended sources. In this generalization the complex degree of coherence between the interfering beams is equivalent to the Fraunhofer diffraction pattern of an aberrated optical system. In 1989 Hariharan and Steel [Appl. Opt. 28, 29 (1989)] commented on this paper and pointed out that the fringe visibility can be zero in the localization plane determined by the conventional pair-of-rays method. Now, we numerically and experimentally show a situation where the equivalent aberrations are such that this finding is verified and that the localization region splits in two, one ahead of and the other behind the classical localization plane. 相似文献
142.
Organic acids occur naturally in foods and have been used in many food products as preservatives because they inhibit the growth of most microorganisms. The acids commonly found in foods differ greatly in both their structure and inhibitory effects for different bacteria. A way to represent relationships between different acids was previously described in which principal components analysis (PCA) was applied to 11 physical and chemical properties of 17 organic acids, to arrive at principal properties. These were used for development of regression models that related the minimum inhibitory concentrations (MICs) of organic acids to their principal properties. Separate MIC models were constructed for six different bacteria. The objective of the present study was to test the predictive capabilities of the organism models using different organic acids from the ones used to construct the original models. MIC predictions were made for three acids for each of the six bacteria for which models were previously constructed. MIC determinations for these acids were then carried out and compared with the predictions; these were in good agreement, thus validating the models. The new data were combined with that obtained previously to produce similar, but slightly stronger models. These had R(2) values between 0.861 and 0.992. 相似文献
143.
Vanna Casson Luca Cecchinato Marco Corradi Ezio Fornasieri Sergio Girotto Silvia Minetto Lorenzo Zamboni Claudio Zilio 《International Journal of Refrigeration》2003,26(8):926-935
This paper is an answer to the need of finding the optimal solution for the throttling system in refrigerating machines using CO2 as working fluid; such a solution must combine reliability, low installation cost and high energy efficiency. To this purpose, different expansion systems are compared by means of a simulation programme, including a new one, operating with a differential valve, a liquid receiver and a thermostatic valve. The typical compression refrigerating cycle performed by CO2 involves transcritical operations and therefore the upper pressure needs to be adjusted to the optimal value, that, unlike the traditional cycle, is not determined by heat transfer. The innovative system here proposed shows an intrinsic self-adjusting capability that leads to COP values quite close to the maximum ones when a fixed suitable value of the differential pressure is chosen, even if the temperature of the secondary fluid varies to a large extent. 相似文献
144.
Absorption of water by room-temperature ionic liquids: effect of anions on concentration and state of water 总被引:1,自引:0,他引:1
Near-infrared (NIR) spectrometry was successfully used for the non-invasive and in situ determination of concentrations and structure of water absorbed by room-temperature ionic liquids (RTILs). It was found that RTILs based on 1-butyl-3-methylimidazolium, namely, [BuMIm]+ [BF4]-, [BuMIm]+ [bis((trifluoromethyl)sulfonyl)amide, or Tf2N]- and [BuMIm]+ [PF6]-, are hydroscopic and can quickly absorb water when they are exposed to air. Absorbed water interacts with the anions of the RTILs, and these interactions lead to changes in the structure of water. Among the RTILs studied, [BF4]- provides the strongest interactions and [PF6]- the weakest. In 24 hours, [Bu-MIm]+ [BF4]- can absorb up to 0.320 M of water, whereas [Bu-MIm]+ [PF6]- can only absorb 8.3 x 10(-2) M of water. It seems that higher amounts of water can be absorbed when the anion of the RTIL can strongly interact and hence stabilize absorbed water molecules by forming hydrogen bonds with them or inducing hydrogen bonds among water molecules. More importantly, the NIR technique can be sensitively used for the noninvasive, in situ determination of absorbed water in RTILs, without any pretreatment, and at limits of detection as low as 3.20 x 10(-3) M. 相似文献
145.
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147.
Eakin Elizabeth G.; Bull Sheana S.; Riley Kimberley M.; Reeves Marina M.; McLaughlin Patty; Gutierrez Silvia 《Canadian Metallurgical Quarterly》2007,26(4):392
Objective: The Resources for Health trial evaluates a social-ecologically based lifestyle (physical activity and diet) intervention targeting low-income, largely Spanish-speaking patients with multiple chronic conditions. Design: A randomized controlled trial was conducted with 200 patients recruited from an urban community health center and assigned to intervention and usual care conditions. Intervention involved 2 face-to-face, self-management support and community linkage sessions with a health educator, 3 follow-up phone calls, and 3 tailored newsletters. Main Outcome Measures: Primary outcomes measured at 6-months were changes in dietary behavior and physical activity. Changes in multilevel support for healthy living were evaluated as a secondary outcome. Results: After adjustment for age, sex, language, and number of chronic conditions, significant intervention effects were observed for dietary behavior and multilevel support for healthy lifestyles but not for physical activity. Conclusion: The Resources for Health intervention provides an effective and practical model for improving health behavior among low-income, Spanish-speaking patients with multiple chronic conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
148.
Pankaj Agrawal Silvia I. Oliveira E. M. Araújo Tomas J. A. Melo 《Journal of Materials Science》2007,42(13):5007-5012
In this work, the rheological, mechanical and morphological properties of nylon 6/polypropylene compatibilized blends were
investigated. Two types of polypropylene were used. One with MFI of 40 g/10 min (PP H103) and the other with MFI of 3.5 g/10 min
(PP H503). The compatibilizers used were polypropylene grafted with 6% of acrylic acid (PPgAA) and polypropylene grafted with
1% of maleic anhydride (PPgMA). The blends composition was 80/20 (wt%) for the PA6/PP binary blends and 80/10/10(wt%) for
the nylon 6/PPgAA/polypropylene and nylon 6/PPgMA/polypropylene ternary blends. Torque rheometry analysis showed that when
PPgAA and PPgMA were added to nylon 6/polypropylene blends, there was an increase in the torque, indicating that reactive
compatibilization has occurred. There is no influence of the polypropylene MFI on the mechanical properties of the uncompatibilized
and compatibilized blends. The impact strength of the blends containing PPgMA were greater than those of the blends containing
PPgAA. The blends containing PPgAA are unstable. SEM analysis showed that PPgMA improves considerably the adhesion between
PA6/PP phases, leading to good mechanical properties. 相似文献
149.
Silvia Angelone Marina Cauhapé Casaux Manuel Borghi Fernando O. Martinez 《Materials and Structures》2016,49(5):1655-1665
Nowadays, the disposal of plastic waste is an issue of major concern worldwide because of its considerable volume and growth. An option to tackle this problem is to recycle this waste. This alternative reduces the quantity of net discards, conserves both material and energy and provides a comparatively simple way to make a substantial reduction in the overall volume of solid waste. The purpose of this study is to investigate an environmentally friendly approach about the influence of recycling different percentages of urban and rural plastic waste by adding them in a dry process on an asphalt mixture, through a comparative laboratory study. The resulting mixtures are analyzed considering their volumetric parameters and the values from diverse laboratory mechanical tests. The performance tests include, Marshall stability, Marshall quotient, indirect tensile strength, fracture energy, resilient modulus, permanent deformation and creep compliance, which were carried out on unmodified and modified hot asphalt mixtures. The obtained results are presented and discussed in this paper showing that the reuse of recycled plastics in asphalt mixtures is a viable alternative that contributes to the reduction of plastic wastes as well as the protection of the environment. 相似文献
150.
Silvia Minardi Bruna Corradetti Francesca Taraballi Monica Sandri Jonathan O. Martinez Sebastian T. Powell Anna Tampieri Bradley K. Weiner Ennio Tasciotti 《Small (Weinheim an der Bergstrasse, Germany)》2016,12(11):1479-1488
Scaffolds functionalized with delivery systems for the release of growth factors is a robust strategy to enhance tissue regeneration. However, after implantation, macrophages infiltrate the scaffold, eventually initiating the degradation and clearance of the delivery systems. Herein, it is hypothesized that fully embedding the poly(d,l ‐lactide‐co‐glycolide acid) microspheres (MS) in a highly structured collagen‐based scaffold (concealing) can prevent their detection, preserving the integrity of the payload. Confocal laser microscopy reveals that non‐embedded MS are easily internalized; when concealed, J774 and bone marrow‐derived macrophages (BMDM) cannot detect them. This is further demonstrated by flow cytometry, as a tenfold decrease is found in the number of MS engulfed by the cells, suggesting that collagen can cloak the MS. This correlates with the amount of nitric oxide and tumor necrosis factor‐α produced by J774 and BMDM in response to the concealed MS, comparable to that found for non‐functionalized collagen scaffolds. Finally, the release kinetics of a reporter protein is preserved in the presence of macrophages, only when MS are concealed. The data provide detailed strategies for fabricating three dimensional (3D) biomimetic scaffolds able to conceal delivery systems and preserve the therapeutic molecules for release. 相似文献