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101.
Effect of dietary cholesterol on bile-acid composition of gall bladder bile from guinea pigs 总被引:1,自引:0,他引:1
The composition of gall bladder bile acids from control and cholesterol-fed, anemic guinea pigs was analyzed by thinlayer-chromatographic
and colorimetric techniques. In both control and cholesterol-fed animals, the gall bladder bile acids constituted about one
third of the total bile solids. The main component of the bile acids of both groups of animals was chenodexycholic acid, which
was predominantly conjugated with glycine. No cholic acid was present although this is the main bile acid in most mammals.
The major difference in bile composition between control and cholesterol-fed animals was the conjugation pattern of chenodeoxycholic
acid. The ratio of glycochenodeoxycholic to taurochenode-oxycholic acid was high, 6.4, for control animals, and decreased
to 2.4 for the cholesterol-fed, anemic animals. Impaired liver function, limited availability of glycine, and greater efficiency
of taurocholanic acids for the disposal of excess cholesterol may be involved in the mechanism for this phenomenon.
Material in this paper has been submitted in partial satisfaction of the requirements for the degree of Master of Science
in Nutition in the Graduate Division of the University of California, Berkeley.
A portion of this material was presented at the 7th International Congress of Biochemistry in Tokyo, Japan, August, 1967. 相似文献
102.
This study is concerned with the inelastic seismic response of nuclear power plant piping systems. Two systems are examined. The first one is an idealized four-equal-span pipe run and the second one consists of two configurations modified from an existing pipe run. Detailed finite element seismic time history analyses are performed using the
computer program. By varying the various geometrical and physical parameters, calculations are made for a total of 76 cases. The results show that ductility generally contributes to reducing the response of piping systems. An empirical relation between the support load reduction factor and support ductility demand is given and a chart and simple procedures are suggested for the design and qualification of piping supports taking ductility into consideration. 相似文献
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ABSTRACTThis paper studies the heat-shielding performance of a beetle forewing to explore how it has excellent thermal protective properties. With an experimental setup of a self-developed heating environment, the heat transfer characteristics of the beetle forewing were tested at 50°C under steady state conditions. Two types of the forewings are considered: cut wing and live wing. The heat transfer results show that the live forewing provides a good heat-shielding performance with the heat-shielding index stabilizing at around 22.1%, which is 60% higher than that of the cut wing. Based on scanning electron microscope images of the microstructure of the cross section of the beetle forewing, a simplified finite element analysis is performed to numerically calculate the heat transfer properties of the forewing. The numerical simulations reveal that the proposed structure of the forewing is good for the design of an effective thermal protection system. In addition, the uncertainty analysis is performed to evaluate the quality of experimental data. These results provide a foundational understanding of the heat transfer characteristics of beetle forewing, which will inspire a promising candidate for an actively cooled thermal protection systems. 相似文献
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Three different semi-interpenetrating polymer network (semi-IPN) polyimide systems were prepared through blending in solution by using 2 different polyimides, BPDA–PDA and PMDA–ODA (E), and 2 different oligomers, bismaleimide (MDAB) and phenylthynyl-terminated BPDA–PDA (BPDA–PDA–PEPA) oligomers. The oligomers are used as crosslinkers to modify the morphology of polyimides. The results show that both MDAB and PEPA are miscible with BPDA–PDA, but MDAB is immiscible with PMDA–ODA (E). Fourier transform infrared spectrum, dynamic mechanical thermal analysis data, and calculated crosslinking density indicate that there are crosslinking networks in these semi-IPN polyimide systems. In addition, the density and wide-angle X-ray diffraction results confirm that the molecular ordering and packing order are reduced by the addition of oligomers for these semi-IPN polyimide systems. © 1998 John Wiley & Sons, Inc. J. Appl. Polym. Sci. 70: 261–272, 1998 相似文献
109.
Investigation of the versatile models for autoimmunity of the ovary and other selected organs has contributed to our understanding of the following aspects of autoimmunity: the mechanism of T cell molecular mimicry; T-->B epitope spreading, as a basis for autoantibody diversification, and as a link between organ-specific and systemic autoimmunity; the localization of genetic loci potentially influencing multiple autoimmune diseases; and the elucidation of regulatory T cells as a component of physiological self tolerance. 相似文献
110.
Tham Nguyen‐Chung Gábor Jüttner Cindy Löser Tung Pham Michael Gehde 《Polymer Engineering and Science》2010,50(1):165-173
The filling process of a micro‐cavity was analyzed by modeling the compressible filling stage by using pressure‐dependent viscosity and adjusted heat transfer coefficients. Experimental filling studies were carried out at the same time on an accurately controlled microinjection molding machine. On the basis of the relationship between the injection pressure and the filling degree, essential factors for the quality of the simulation can be identified. It can be shown that the flow behavior of the melt in a micro‐cavity with a high aspect ratio is extremely dependent on the melt compressibility in the injection cylinder. This phenomenon needs to be considered in the simulation to predict an accurate flow rate. The heat transfer coefficient between the melt and the mold wall that was determined by the reverse engineering varies significantly even during the filling stage. With increasing injection speed and increasing cavity thickness, the heat transfer coefficient decreases. It is believed that the level of the cavity pressure is responsible for the resulting heat transfer between the polymer and the mold. A pressure‐dependent model for the heat transfer coefficient would be able to significantly improve the quality of the process simulation. POLYM. ENG. SCI., 2010. © 2009 Society of Plastics Engineers 相似文献