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791.
Sunil K. Srivastava Tripurari Saran Jagadish Sinha Laxminarayanapuram V. Ramachandran Siripurapu K. Rao 《Fuel》1988,67(12):1683-1684
Pyrolysis of several Indian coals of different rank in the presence of NaOH showed that the best yield of hydrogen was obtained from medium rank (C, 83.5%) Poniati-Girimint coal. With this coal, other alkalis (Ca(OH)2, CaCO3, Na2CO3) gave much less hydrogen, but significantly more methane in the product gas. 相似文献
792.
V.S Ramachandran 《Cement and Concrete Research》1976,6(5):623-631
Following addition of 0.1, 0.25, 0.35, 0.5 and 1.0 per cent triethanolamine, studies have been made of the hydration and hardening characteristics of (a) tricalcium aluminate, (b) tricalcium aluminate + gypsum, (c) tricalcium silicate, (d) dicalcium silicate, and (e) portland cement. Triethanolamine (TEA) accelerated the hydration of 3CaO.Al2O3 and 3CaO.Al2O3-CaSO4.2H2O systems and extended the induction period of the hydration of 3CaO.SiO2. In portland cement paste TEA decreased the strength at all ages and setting characteristics were drastically altered, especially at higher TEA contents. Evidence was obtained also of the formation of a complex of TEA with the hydrating silicate phase. 相似文献
793.
Olfactory sensitivity of two sympatric species of rice leaf folders (Lepidoptera: Pyralidae) to plant volatiles 总被引:2,自引:0,他引:2
R. Ramachandran Z. R. Khan P. Caballero B. O. Juliano 《Journal of chemical ecology》1990,16(9):2647-2666
Electroantennograms (EAGs) were recorded from male and female moths of two sympatric leaf folder species,Cnaphalocrocis medinalis (Gue-née) andMarasmia patnalis Bradley (Lepidoptera: Pyralidae) to 91 volatile chemicals of plant origin. Responses of both leaf folder species were similar to all compounds except to three monoterpenes--myrcene, menthone, and isomenthone- and two sesquiterpenes-cis-nerolidol and isophytol. Response ofM. patnalis, an oligophagous leaf folder, to these compounds was higher compared with that of polyphagousC. medinalis. EAG responses of males to saturated and unsaturated aliphatic aldehydes were significantly higher than those of conspecific females in both species. A higher response ofC. medinalis males also was observed for 1-nonanol, 3-nonen-2-one, andtrans, trans-2,6-dimethyl-2,4,6-octatriene. In contrast, females of both species responded more to monoterpenes, borneol, isoborneol, and fenchyl alchohol. Response ofC. medinalis female was higher for terpinen-4-ol, carveol, dihydrocarveol, (–)-myrtenal, and perillaldehyde. In both species and sexes, high EAG responses were recorded for compounds of the green leaf odor complex. EAG responses to nonanal and hexanal were maximum among the aliphatic aldehydes while 1-hexanol elicited the highest response among the alcohols tested. EAG responses to terpene compounds-citronellal,-terpineol, and (–)-myrtenal-were equal to the response to 1-hexanol. While all compounds tested elicited a negative potential, thymol and carvacrol elicited a positive EAG potential. The EAG data are discussed with regard 相似文献
794.
Lingappa Rangaraj Canchi Divakar Vikram Jayaram 《Journal of the American Ceramic Society》2004,87(10):1872-1878
Dense composites in the Ti-B-N system have been produced by reactive hot pressing of titanium and BN powders. The effect of the addition of a small amount of nickel (1–3 wt%) on the reaction kinetics and densification of TiN–TiB2 (40 vol%) composite has been studied. Composites of ∼99% of theoretical density have been produced at 1600°C under 40 MPa for 30 min with 1% nickel. The hardness and fracture toughness of these composites are 24.5 ± 0.97 GPa and 6.53 ± 0.27 MPa·m1/2 , respectively. The microstructural studies on samples produced at lower temperatures indicate the formation of a transient liquid phase, which enhances the kinetics of the reaction and densification of the composite. 相似文献
795.
S. Vijayan C. Ramachandran D. O. Shah 《Journal of the American Oil Chemists' Society》1981,58(4):566-573
Physical properties and molecular packing in surfactant aggregates of the surfactant formulation 5% (w/w) TRS 10–410 (a petroleum
sulfonate), 3% (w/w) isobutanol and desired quantities of sodium chloride in distilled water were studied using electron spin
resonance (ESR) technique and pH, density, viscosity, screen factor, specific conductance, surface tension and free sodium
ion measurements of fresh and aged solutions. The results suggested that both salt concentration and aging lead to changes
in molecular packing of surfactant aggregates. At optimal salinity, the order parameter was a maximum. With increasing salt
concentration, the correlation time increases initially and decreases at higher salt concentration. Various physical property
data substantiate the observed microstructural changes. A detailed discussion is presented of the interrelations of these
parameters operative in this complex surfactant formulation.
Presently with the Whiteshell Nuclear Research Establishment, Atomic Energy of Canada Ltd., Pinawa, Manitoba, Canada ROE 1LO. 相似文献
796.
V.S. Ramachandran 《Cement and Concrete Research》1979,9(6):677-684
DTA is applied to estimate Ca(OH)2 in cementitious phases by determining the peak areas caused by the decomposition of Ca(OH)2 to CaO+H2O. In the hydration of C3S generally, the chemical method yields slightly higher values. DTA is also used as a monitoring technique in preparing a practically Ca(OH)2-free product from hydrated portland cement or hydrated C3S. Hydrated portland cement or C3S has now been exposed to an unsaturated Ca(OH)2 solution and extraction continued until the sample indicate no endothermal peak for Ca(OH)2. The thermal method permits determination of the rate of formation of Ca(OH)2 in portland cement hydrated in the presence of 0, 1, 2 and per cent CaCl2. 相似文献
797.
The pace of development in the world has increased over the years and with it, the use of hi-tech gadgets, consumer durables, automobiles, etc. has also gone up. In this context, as resources become more and more scarce, there are multiple challenges that emerge both from a sustainable development perspective, and from the perspective of meeting profitability objectives of a firm. Remanufacturing has come up in a big way as an answer to these challenges, but firms are struggling with respect to revenue management of this nascent area. We assess the current literature and distil the key factors that firms need to consider as they assimilate remanufacturing in their operations and revenue management strategy. We provide an assessment of white spaces in research in this area and also outline the directions for future research. 相似文献
798.
We introduce a new class of dynamic graph algorithms called quasi-fully dynamic algorithms , which are much more general than backtracking algorithms and are much simpler than fully dynamic algorithms. These algorithms
are especially suitable for applications in which a certain core connected portion of the graph remains fixed, and fully dynamic
updates occur on the remaining edges in the graph.
We present very simple quasi-fully dynamic algorithms with O(log n) worst-case time per operation for 2-edge connectivity and O(log n) amortized time per operation for cycle equivalence. The former is deterministic while the latter is Monte-Carlo-type randomized.
For 2-vertex connectivity, we give a deterministic quasi-fully dynamic algorithm with O(log
3
n) amortized time per operation.
The quasi-fully dynamic algorithm we present for cycle equivalence (which has several applications in optimizing compilers)
is of special interest since the algorithm is quite simple, and no special-purpose incremental or backtracking algorithm is
known for this problem.
Received October 26, 1998; revised October 1, 1999, and April 15, 2001. 相似文献
799.
Ramachandran Krishna Kumar Sikdar Biplab 《Parallel and Distributed Systems, IEEE Transactions on》2010,21(3):367-378
This paper presents a queuing model to evaluate the latency associated with file transfers or replications in peer-to-peer (P2P) computer systems. The main contribution of this paper is a modeling framework for the peers that accounts for the file size distribution, the search time, load distribution at peers, and number of concurrent downloads allowed by a peer. We propose a queuing model that models the nodes or peers in such systems as M/G/1/K processor sharing queues. The model is extended to account for peers which alternate between online and offline states. The proposed queuing model for the peers is combined with a single class open queuing network for the routers interconnecting the peers to obtain the overall file transfer latency. We also show that in scenarios with multipart downloads from different peers, a rate proportional allocation strategy minimizes the download times. 相似文献
800.
Thomas Glaser Constantijn F.W. Sanders Fu.Y. Wang Ian T. Cameron James D. Litster Jonathan M.-H. Poon Rohit Ramachandran Charles D. Immanuel Francis J. Doyle 《Journal of Process Control》2009,19(4):615-622
This paper details a methodology for the design of a model predictive controller for a continuous granulation plant. The work is based on a non-linear one-dimensional population balance model (1D-PBM), which was parameterized using experimental step test data generated at a continuous granulation pilot plant installed at the University of Queensland, Australia. The main objective was to operate the granulator under optimal conditions while off-specification material was fed back into the granulator to increase the economy of the process. The final algorithm design combines elements of model predictive control (MPC) with gain scheduling to cancel non-linearities in the recycle flow. A model directly identified from the step test data was the basis for testing a model predictive controller. Simulations show that the efficiency and robustness of this granulation process can be improved by applying the proposed control strategy. Ongoing work focuses on the implementation of the proposed control strategy on a full scale industrial plant. 相似文献