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31.
The advertisement placement problem deals with space and time sharing by advertisements on the Internet. Consider a Web page containing a rectangular display area (e.g., a banner) in which advertisements may appear. The display area can be utilized efficiently by allowing several small ads to appear simultaneously side by side, as well as by cycling through a schedule of ads, allowing different ads to be displayed at different times. A customer wishing to purchase advertising space specifies an ad size and a display count, which is the number of times their ad should appear during each cycle. The scheduler may accept or reject any given advertisement, but must be able to schedule all accepted ads within the given time and space constraints. Each advertisement has a non-negative profit associated with it, and the objective is to schedule a maximum-profit subset of ads. We present a (3 + )-approximation algorithm for the general problem, as well as (2 + )-approximation algorithms for two special cases. 相似文献
32.
Cleaner production (CP) can be good business. To address constraints related to financing CP and to look for ways to overcome them, the United Nations Environment Programme, Division of Technology, Industry and Economic (UNEP/DTIE), has been implementing since 1999 a project "Strategies and mechanisms for promoting cleaner production investment in developing countries". The project is coming to an end in February 2003. Through field testing and adaptation and in partnership with experts in industrialised and developing countries and economies in transition, it has generated a series of guides, checklists and training packages. Over 3,000 persons attended the over 100 1- or 2-day courses delivered by national institutions in five demonstration countries. The project has also contributed to making preventive approaches and efficient resource management part of awareness raising and training activities by some development finance institutions and the UNEP Finance Initiatives. Proposals on innovative financing schemes have been made in several workshops for banks and donors in 2002. In addition to the special financing issue of the Journal of Cleaner Production (published in March 2003), articles on links between CP, financing and accounting have been contributed to professional publications.Although the project's demonstration activities have focused on five countries in Africa, Asia and Central America, its conclusions, recommendations and outputs are of direct relevance also to other developing countries and economies in transition. The integration of preventive strategies into investment decision making processes is a challenge both in the industrialised and in developing countries in the region. This paper summarises the lessons learned through the project and presents the recommendations, tools and instruments available for adaptation and use by CP promoters, financial institutions and business schools. 相似文献
33.
Jyrki Ari Timo Mika 《AEUE-International Journal of Electronics and Communications》2007,61(2):118-126
In this paper we present a packet scheduling method which guarantees bandwidth of the connection and optimizes revenue of the network service provider. A closed form formula for updating the adaptive weights of a packet scheduler is derived from a revenue-based optimization problem. The weight updating procedure is fast and independent on the assumption of the connections’ statistical behavior. The features of the algorithm are simulated and analyzed with and without a call admission control (CAC) mechanism. We also show in context with the CAC procedure a mechanism for guaranteeing a specified mean bandwidth for different service classes. 相似文献
34.
35.
Yongxiang Yang Ari Jokilaakso Pekka Taskinen Markku Kytö 《JOM Journal of the Minerals, Metals and Materials Society》1999,51(5):36-40
This article describes the use of a general-purpose computational-fluid-dynamics code for improving and optimizing waste-heat
boilers in the Outokumpu flash smelting process. The codes offer opportunities to study the transport phenomena for fluid
and particulate flow and heat and mass transfer. The simulation includes gas- and dust-flow behaviors and gas cooling by convection
and radiation. The results were used in the boiler modification for increased capacity and higher cooling efficiency. The
modified boiler, with its unique design, has been in use at Outokumpu’s Harjavalta copper smelter since June 1995 with excellent
performance.
For more information, contact Y. Yang, Delft University of Technology, Raw Materials Technology/Applied Earth Sciences, Mijnbouwstraat
120, Delft, 2628 RX, Netherlands; telephone 31-15-278-2542; fax 31-15-278-2836; e-mail Y.Yang@ta.tudelft.nl. 相似文献
36.
Ari Geiger Ephraim Nissan Ariel Stollman 《Information & Communications Technology Law》2001,10(1):21-37
For the purposes of starting to tackle, within artificial intelligence (AI), the narrative aspects of legal narratives in a criminal evidence perspective, traditional AI models of narrative understanding can arguably supplement extant models of legal narratives from the scholarly literature of law, jury studies, or the semiotics of law. Not only: the literary (or cinematic) models prominent in a given culture impinge, with their poetic conventions, on the way members of the culture make sense of the world. This shows glaringly in the sample narrative from the Continent-the Jama murder, the inquiry, and the public outcry-we analyse in this paper. Apparently in the same racist crime category as the case of Stephen Lawrence's murder (in Greenwich on 22 April 1993) with the ensuing still current controversy in the UK, the Jama case (some 20 years ago) stood apart because of a very unusual element: the eyewitnesses identifying the suspects were a group of football referees and linesmen eating together at a restaurant, and seeing the sleeping man as he was set ablaze in a public park nearby. Professional background as witnesses-cum-factfinders in a mass sport, and public perceptions of their required characteristics, couldn't but feature prominently in the public perception of the case, even more so as the suspects were released by the magistrate conducting the inquiry. There are sides to this case that involve different expected effects in an inquisitorial criminal procedure system from the Continent, where an investigating magistrate leads the inquiry and prepares the prosecution case, as opposed to trial by jury under the Anglo-American adversarial system. In the JAMA prototype, we tried to approach the given case from the coign of vantage of narrative models from AI. 相似文献
37.
The effects of calcium carbonate (CaCO3) particle size on the fusion and rheological behaviors of rigid poly(vinyl chloride) (PVC) composites prepared in a Haake torque rheometer were investigated by means of torque data recorded during processing. Increasing the number of particles in the same blend volume by decreasing the particle size resulted in increasing frictional forces. This increase led in turn to increased fusion torque and decreased fusion time and temperature. The power‐law‐index values of the composites increased with decreasing particle size except for 25‐nm CaCO3. The viscosities of all composites were found to decrease with shear rate; therefore, high pseudoplasticity was observed. At a particular rotor speed, viscosity of the composites decreased with decreasing particle size except for 25‐nm CaCO3. The overall results showed that the particle size of CaCO3 altered the fusion characteristics and rheological behavior of PVC. J. VINYL ADDIT. TECHNOL., 2010. © 2010 Society of Plastics Engineers 相似文献
38.
Removal of sulphate and toxic elements from the leachate of a field landfill lysimeter (112m(3)), containing municipal solid waste incineration (MSWI) bottom ash, was studied. The leachate was treated in two parallel laboratory upflow anaerobic sludge blanket (UASB) reactors without and with ethanol as additional carbon source. With ethanol more than 65% of sulphate was removed, while without ethanol removal was negligible. The treatment removed Ba, Ca, Cu, Mn, Mo, Ni, Pb, Tl, Sb, Se, Sr, and Zn of the studied 35 trace and other elements. The sequential extraction of the reactor sludge at the end of runs confirmed that with a few exceptions (Ba, Ca, and Cu) the main mechanism by which the elements were removed was precipitation as sulphides. 相似文献
39.
40.
Jie Duanmu E. Kristofer Gamstedt Andrey Pranovich Ari Rosling 《Composites Part A》2010,41(10):1409-1418
In a previous work we introduced a new family of thermoset composites of softwood fiber and allylglycidyl ether modified potato starch (AGE-starch with a degree of substitution of 1.3 and 2.3) prepared by hot pressing. To improve the processability of AGE-starch with a DS = 1.3 (LDS-3) and to increase hygromechanical properties, the LDS-3 matrix has now been partially degraded by α-amylase at 45 °C (pH 6) for 0.5, 6 and 18 h. The study shows that already a 30 min enzymatic hydrolysis has a marked effect on the modified starch molecular weight and its thermal properties. The new composites with enzyme hydrolyzed AGE-starch, generically named D-LDS-3, showed good fiber dispersion and excellent interface between the fiber and matrix as studied by SEM. Premixes of D-LDS-3 matrix and fiber showed improved processability. The water vapor absorption was evaluated at 43.2% and 82.2% RH and the stiffness and strength properties were measured. The water uptake was shown to be reduced. The strength of neat matrix D-LDS-3-6 at ambient 68% RH reached 63 MPa and Young’s modulus 3200 MPa and with 40 wt.% wood fiber reinforcement impressive 128 MPa and 4500 MPa, respectively. 相似文献