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101.
The authors examined the thermal change in the aroma profile of myrrh. The fresh odor of raw myrrh and its hexane extract depended on the amount of (E)-13-ocimene. Myrrh was extracted with hexane to avoid inducing changes in the constituents and odor. The main constituent, (E)-L3-ocimene (group A; low boiling point), and the other constituents (group B; high boiling point) of the hexane extract were separated by bulb-to-bulb distillation. The constituents of groups A and B were analyzed over time by nuclear magnetic resonance analysis and the odors were evaluated. Myrrh's odor depended on both the amount of thermally unstable (E)-[3-ocimene, which contributed to the fresh odor, and the constituents of group B (thermally stable), which contributed to the myrrh-like odor. Six compounds (c~-santalene, (Z)-a-bisabolene, c~-bergamotene, (E)-ct-santalal, c~-photosantalol and campherenol) were isolated from group B. No individual group B component had a myrrh-like odor, although the combined odor of group B was myrrh like. The authors demonstrated that the aroma profile of myrrh depends on the thermal instability of (E)-~-ocimene and a combination of six thermally stable terpenes with similar molecular structures.  相似文献   
102.
Micro-mesoporous bimodal carbon nanospheres with high surface areas were synthesized by a combined use of surfactant templating technique and BaO2 chemical activation one. Starting spherical nanopolymer/surfactant composites were prepared by the NaOH-catalyzed reaction of resorcinol (R) and formaldehyde (F) in the presence of cetyltrimethylammonium bromide (CTAB) as a core template and 1,3,5-trimethylbenzene (TMB) and tert-butanol (t-BuOH) as cosurfactants. After pretreatment with hydrochloric acid, the composite materials were calcined at 1000 °C in N2 coexistent with varying weight ratios of BaO2 to RF polymer ranging from 0 to 11. It produced micro-mesoporous bimodal carbon nanospheres of 124–143 nm diameter, with specific surface areas as high as 1884 m2 g−1 or up to 3301 m2 g−1, in contrast to microporous ones with smaller surface areas obtained at low BaO2-loadings. The electrochemical double layer capacitance of the resulting nanocarbons in 0.5 M H2SO4 showed a marked increase with specific surface areas, up to as high as 219 F g−1 for the highest surface area carbon material.  相似文献   
103.
We investigated crystal structure, and thermal, swelling, and deformation behaviors of dried tetrafunctional (polyethylene glycol) gel, Tetra-PEG gel, with narrow molecular distribution. Tetra-PEG gel consists of two kinds of symmetrical tetrahedron-like PEG macromonomers with a fixed molecular weight. In spite of network structure with rather small molecular weight between cross-links (Mc) (≈5000), the dried Tetra-PEG gels were found to be capable of crystallization. The crystalline melting temperature (Tm) and the degree of crystallinity (Xc) of dried Tetra-PEG gels obtained by differential scanning calorimetry (DSC) were substantially constant against the polymer volume fraction at preparation (?0). Furthermore, the corrected elastic modulus (G) of dried Tetra-PEG gels did not depend on ?0. These experimental results indicate that the there exist negligible entanglements in the dried Tetra-PEG network irrespective of ?0. In other words, Tetra-PEG gels do not have significant topological inhomogeneities.  相似文献   
104.
The Pacific Tracker (PacTrac) is a computer program designed to analyse food intakes of individuals from the Pacific Region. PacTrac’s original output included servings of daily intake of food groups according to the United States Food Guide Pyramid, nutrient intake recommendations, and a comparison to other national nutrition recommendations. PacTrac was made available for public use through the Hawaii Foods website (hawaiifoods.hawaii.edu). PacTrac2 is an updated and expanded version of PacTrac that uses the United States MyPyramid/MyPlate food groups in household units of daily intake, rather than servings. In addition, the PacTrac2 includes a physical activity analysis tool which quantifies minutes of physical activities and their intensities based on energy estimates from the compendium of physical activity and research on children. An Expert System (ES) – a computerised decision tree to guide behaviour change – was developed using information on self-efficacy and stage of readiness to change, and the fruit and vegetable intake and physical activity information from PacTrac2. The ES produces reports for the child, the parent/guardian, and the child’s physician with child-specific strategies, targeted behavioural information, and feedback tailored to the child. PacTrac2-ES was designed for the Pacific Kids DASH for Health (PacDASH) intervention study, conducted in the Kaiser Permanente health care system in Hawaii. The intervention is based on the child’s self-efficacy and stage of readiness to change intake of fruits and vegetables and physical activity, with a goal of maintaining body weight to prevent obesity. The intervention is complemented with stage-based mailers addressing the environment for physical activity and fruit and vegetable intake and newsletters that address related behaviours (sedentary activity and a DASH eating approach). This project is the first to expand the PacTrac to contain children’s foods and physical activities from the Pacific Region and to use current US MyPyramid/MyPlate food and physical activity analysis and guidance systems, and to develop and implement an Expert System for fruits, vegetables and physical activity of 5–8-year-old children. The PacTrac2-ES was used in the PacDASH study and will be used for other programs to promote healthy eating and physical activity of children in the Pacific Region.  相似文献   
105.
The gaseous diffusion coefficients of methyl bromide (CH3Br) and methyl iodide (CH3I) into dry air, nitrogen, and oxygen have been measured in the temperature range 303–453 K and at atmospheric pressure via the Taylor dispersion method. Both for methyl bromide and methyl iodide, the diffusion coefficients do not vary in practice on substituting pure nitrogen or oxygen for dry air. The diffusion coefficients for methyl iodide are systematically smaller than those for methyl bromide by about 11%. For the methyl iodide‐oxygen system, the effect of the thermal decomposition of methyl iodide has been observed at 453 K. The present results can be reproduced well by the functional form D = ATB, where D (cm2s?1) is the diffusion coefficient at 101 325 Pa (1 atm) and T (K) is the absolute temperature. The constants A and B are as follows: methyl bromide‐(air, nitrogen, oxygen), A = 5.57 × 10?6, B = 1.76; methyl iodide‐(air, nitrogen, oxygen), A = 5.26 × 10?6, B = 1.75. © 2009 Wiley Periodicals, Inc. Heat Trans Asian Res; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20255  相似文献   
106.
All-solid-state switchable mirror glass was prepared by magnetron sputtering. The device exhibited the multi-layer structure of Mg4Ni/Pd/Ta2O5 on WO3/ITO/glass substrate. The Mg4Ni, Pd, and Ta2O5 in the device acted as optical switches, proton injector and solid electrolyte, respectively. Reactive DC magnetron sputtering was employed as a new deposition method for Ta2O5 electrolyte thin film for the device. The transmittance of the device, at a wavelength of 670 nm using reactive DC-sputtered Ta2O5 thin film, reached 0.1% (a reflective state) to 48% (a transparent state). The transmittance change occurred in less than 40 s when 5 V was applied, and the switching speed was 60 times faster than that of the device using reactive RF-sputtered Ta2O5 thin film.  相似文献   
107.
An electrochromic (EC) switchable mirror glass can change between a reflective state and a transparent state with voltage application. The conventional device has a multilayer of Mg4Ni/Pd/Al/Ta2O5/WO3/indium-tin oxide on a transparent substrate. A palladium thin film was used as the proton injection layer. For practical use, we attempted to reduce the amount of palladium thin film from the viewpoints of the reduction in total fabrication cost and the efficient use of resources. The thickness of the film was related to the optical switching properties of the device. Although the device with a 1-nm-thick palladium film showed a high transmittance of 63% in the transparent state, its low switching durability was not suitable for practical application.Moreover, we were able to adapt a palladium-based alloy (Pd0.8Ag0.2) which is a well-known hydrogen permeation membrane as the proton injection layer to reduce the amount of palladium thin film. As a result, we found that a 4-nm-thick Pd-Ag thin film has good adaptability to the EC switchable mirror.  相似文献   
108.
An electrochromic switchable mirror on a flexible plastic sheet was developed taking into consideration practical use, low cost and high adaptability. The mirror has a multilayer of Mg4Ni/Pd/Al/Ta2O5/WO3, which was fabricated by DC magnetron sputtering on an ITO-coated PET sheet. In the previous research, when the mirror was exposed to air for a long period of time, its optical switching properties disappeared. This work focused on the mechanism of degradation of the mirror in different environments. When the mirror was stored in a desiccator for 50 days as a means of preservation, its switching speed was seven times higher as compared with the mirror exposed to air. It is also well known that oxygen and moisture in air easily penetrate PET sheets. The features of the PET sheet strongly affected the durability of the optical switching layer. When the state of the optical switching layer was changed to nonmetallic due to the formation of oxide and hydroxide, the optical switching properties almost disappeared.  相似文献   
109.
Natural frequencies and buckling stresses of angle-ply laminated composite plates are analyzed by taking into account the effects of shear deformation, thickness change and rotatory inertia. By using the method of power series expansion of displacement components, a set of fundamental dynamic equations of a two-dimensional higher-order theory for thick rectangular laminates subjected to in-plane stresses is derived through Hamilton's principle. Several sets of truncated approximate theories are applied to solve the eigenvalue problems of a simply supported thick laminated plate. In order to assure the accuracy of the present theory, convergence properties of the fundamental natural frequency are examined in detail. Numerical results are compared with those of the published existing theories. The modal displacement and stress distributions in the thickness direction are obtained and plotted in figures. The present global higher-order approximate theories can predict the natural frequencies, buckling stresses and modal stresses of thick multilayered angle-ply composite laminates accurately within small number of unknowns which is not dependent on the number of layers.  相似文献   
110.
Natural frequencies and buckling stresses of a thick isotropic plate on two-parameter elastic foundations are analyzed by taking into account the effect of shear deformation, thickness change, and rotatory inertia. Using the method of power series expansion of the displacement components, a set of fundamental dynamic equations of a two-dimensional, higher-order theory for thick rectangular plates subjected to in-plane stresses is derived through Hamilton's principle. Several sets of truncated approximate theories are used to solve the eigenvalue problems of a simply supported thick elastic plate. To assure the accuracy of the present theory, convergence properties of the minimum natural frequency and the buckling stress are examined in detail. The distribution of modal transverse stresses are obtained by integrating the three-dimensional equations of motion in the thickness direction. The present approximate theories can accurately predict the natural frequencies and buckling stresses of thick plates on elastic foundations as compared with Mindlin plate theory and classical plate theory.  相似文献   
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