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91.
In order to study the chaotic behavior of vibrational thermal convection in a square enclosure, a calculation method and the features of the average Nusselt number with vibration frequency were precisely examined. In the computation, the Prandtl number, the Rayleigh number, and the vibration Grashof number were held constant at 0.71, 104, and 106, respectively. The angular frequency of vibration was changed in the range between 10 and 7680. The results showed that the phenomena could be predicted with the calculation method adopted in this paper and the change in the time‐dependent characteristics of surface‐averaged Nusselt number with the angular frequency of vibration could be analyzed well with the power spectra. These changes were characterized by the five regimes proposed by Fu and Shieh. Moreover, it was clarified that the region where the hysteresis phenomena were detected corresponded to the one where the variation of the surface‐averaged Nusselt number was irregular and aperiodic. © 2000 Scripta Technica, Heat Trans Asian Res, 29(7): 545–558, 2000 相似文献
92.
93.
Hideshi Yokoyama Ryuta Mizutani 《International journal of molecular sciences》2014,15(11):20321-20338
Exposure to the ultraviolet component of sunlight causes DNA damage, which subsequently leads to mutations, cellular transformation, and cell death. DNA photoproducts with (6-4) pyrimidine-pyrimidone adducts are more mutagenic than cyclobutane pyrimidine dimers. These lesions must be repaired because of the high mutagenic potential of (6-4) photoproducts. We here reviewed the structures of (6-4) photoproducts, particularly the detailed structures of the (6-4) lesion and (6-4) lesion-containing double-stranded DNA. We also focused on interactions with their binding proteins such as antibody Fabs, (6-4) photolyase, and nucleotide excision repair protein. The (6-4) photoproducts that bound to these proteins had common structural features: The 5''-side thymine and 3''-side pyrimidone bases of the T(6-4)T segment were in half-chair and planar conformations, respectively, and both bases were positioned nearly perpendicularly to each other. Interactions with binding proteins showed that the DNA helices flanking the T(6-4)T segment were largely kinked, and the flipped-out T(6-4)T segment was recognized by these proteins. These proteins had distinctive binding-site structures that were appropriate for their functions. 相似文献
94.
In our previous studies, sintered and heat-treated alloy steels (Fe−6Ni−0.5Mo−0.4C (mass%)) produced by a MIM process showed
excellent mechanical properties of 2000 MPa tensile strength and 5% elongation. This was attributed to the solid solution
strengthening and the mezzo-heterogenous microstruture, which consisted of martensite or retained austenite (Ni and Mo rich
phases) surrounded by a network of tempered martensite. This study has been performed to clarify the effect of Mo on the mezzo-heterogeneous
microstructure and the mechanical properties of MIM processed and sintered alloy steels (Fe−6Ni−0.4C) with varying Mo content
(0.5–2 mass%). The tensile properties of the heat-treated steels with added 2 mass% Mo were lower than those of the steels
with added 0.5 mass% Mo. The reduction in the tensile properties, particularly the appearance of large pores formed at the
original location of Mo power through the transient liquid phase formation and the low hardness of the matrix, was due to
the low sintered density. By using mechanically milled fine Ni and Mo powders, the heat-treated steel (Fe−6Ni−2Mo−0.4C) showed
excellent properties, including tensile strength of 1800 MPa and ductility of 2.2% elongation.
This article is based on a presentation made in the symposium “The 3rd KIM-JIM Joint Symposium on Advanced Powder Materials”,
held at Korea University, Seoul, Korea, October 26–27, 2001 under auspices of The Korean Institute of Metals and Materials
and The Japan Institute of Metals. 相似文献
95.
Hideshi Ishida Shojiro Kawase Hideo Kimoto 《International Journal of Heat and Mass Transfer》2006,49(25-26):5035-5048
In this study we have proposed an accurate and simple method to evaluate the Lyapunov spectrum. The method is suitable for any discretization method that finally expresses a governing equation system in the form of an ordinary differential equation system. The method was applied to evaluate up to the second largest Lyapunov exponents for natural convection in a rectangular cavity with heated and cooled side walls. The main results are as follows: (1) the largest and second largest Lyapunov exponents can be evaluated without any parameters that affects the exponents. (2) The second largest Lyapunov exponent makes it possible to classify quantitatively thermal convection fields into five regimes against the Rayleigh number and to clarify the transition route from steady state to chaos by identifying the first and second Hopf bifurcations. (3) The fluctuation in thermal convection fields just over the critical Rayleigh number at which Hopf bifurcation occurs can be quantitatively explained by using normalized Lyapunov vectors, associated with the computation of the Lyapunov exponents, just under the critical point. 相似文献
96.
The enantiomerically pure synthesis of [(2'S, 3'S)-bis(hydroxymethyl)pyrrolidin-1-yl] thymine 17 and -adenine 20 was achieved via construction of the base on the 1-amino-pyrrolidine 15, and their anti-HSV-1 and -2, and anti-HIV-1 activities were evaluated. 相似文献
97.
In this paper, the time‐dependent characteristics of natural convection in a vertical slot with hot and cold side walls were experimentally examined. In the experiment, the test liquid was a glycerine–water mixture (80 wt%) and the Prandtl number in the center of the slot was held constant at 295. On the other hand, the Grashof number was varied in the range between 370 and 3.06 × 103. As a result, it was revealed that low‐pass filtering for the time evolution data of temperature made it possible to compute the largest Lyapunov exponents precisely. Secondary flow cells are observed in both chaotic and nonchaotic regions. Moreover, the secondary flow cells appeared in regions where the power spectrum of temperature fluctuation was regarded as significant and where the autocorrelation function decreased rapidly with time. © 2000 Scripta Technica, Heat Trans Asian Res, 30(1): 40–53, 2001 相似文献
98.
The preparation of asymmetric flat membranes from a series of novel aromatic polyamides comprising 3,3′‐diaminodiphenylsulfone and a comonomer with a carboxyl group(&BOND;COOH) were studied and the measurements of reverse osmosis (RO) performance and chlorine resistance were carried out. It was confirmed that the introduction of comonomer with a carboxyl group (MC or Tm) to the aromatic polyamides (3I or 3T) comprising 3,3′‐diaminodiphenylsulfone was very effective for the improvement of its RO performance. In particular, 3T‐MC(30), which was prepared from terephthaloyl dichloride and mixed diamine components of 3,3′‐diaminodiphenylsulfone and 3,5‐diaminobenzoic acid, exhibited not only some potential for sea water desalination (FR = 159 L/m2 day, Rj = 98.3%) but also higher chlorine resistance than conventional Nomex‐type aramid [MI‐MC(0)]. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 505–513, 2001 相似文献
99.
Tanaka T. Hibino Y. Hashimoto T. Kasahara R. Inoue Y. Himeno A. Itoh M. Abe M. Oohashi H. Tohmori Y. 《Electronics letters》2001,37(2):95-96
A planar lightwave circuit (PLC)-type hybrid external cavity laser, integrated with a front-monitor photodiode (PD) on Si has been successfully fabricated. Polymer-embedded grooves are incorporated in the cavity to suppress mode hopping, and the optical power of the laser was stabilised from 18 to 56°C with no mode hopping 相似文献
100.
Hiroaki Niitsuma Michael Fehler Robert Jones Stephen Wilson James Albright Andrew Green Roy Baria Kazuo Hayashi Hideshi Kaieda Kazuhiko Tezuka Andy Jupe Thomas Wallroth Franois Cornet Hiroshi Asanuma Hirokazu Moriya Koji Nagano W. Scott Phillips James Rutledge Leigh House Alain Beauce Doug Alde Richard Aster 《Geothermics》1999,28(4-5)
Seismic and borehole measurements provide significant information about HDR/HWR reservoirs that is useful for reservoir development, reservoir characterization, and performance evaluation. Both techniques have been widely used during all HDR/HWR development projects. Seismic measurements have advanced from making passive surface measurements during hydraulic fracturing to making passive observations from multiple boreholes during all phases of HDR/HWR development, as well as active seismic measurements to probe regions of the reservoir deemed to be of interest. Seismic data provide information about reservoir extent, locations and orientations of significant fractures, and areas of thermal drawdown. Recent advances include the ability to examine structures within the seismically active zone using statistics-based techniques and methods such as seismic tomography. Seismic method is the only means to obtain direct information about reservoir characteristics away from boreholes. Borehole measurements provide high-resolution information about reservoir characteristics in the vicinity of the borehole. The ability to make borehole measurements has grown during the course of HDR/HWR development as high temperature tools have been developed. Temperature logging, televiewer logs, and electrical property measurements have been made and shown to provide useful information about locations of fractures intersecting wellbores, and regions where water leaves and enters injection and production wellbores, respectively. 相似文献