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1.
Sinéad C. Mac Namara Maria M. Garlock David P. Billington 《Canadian Metallurgical Quarterly》2007,21(2):152-156
Steam generator replacement at nuclear power plants requires large construction openings in nuclear containment structures. This study examines the effects of such openings placed in a 61?cm (2?ft) thick dome of a shield building. The dome is cast in two layers, and the limiting cases of the two layers acting as one and the lower layer carrying the entire load are considered. Without openings, the stresses due to dead load in the structure are very low when compared to the material strength. With openings, the loads are easily redistributed around the opening, and the maximum stresses for the conservative case are between three and four and one-half times larger than in the original structure with no openings. The extent of the affected area around the holes is relatively small. Smooth corners in the openings are necessary to avoid high local stress concentrations. 相似文献
2.
Miguel A. Martínez-del-Amor Luis F. Macías-Ramos Luis Valencia-Cabrera Mario J. Pérez-Jiménez 《Natural computing》2016,15(4):565-573
Population Dynamics P systems are a type of multienvironment P systems that serve as a formal modeling framework for real ecosystems. The accurate simulation of these probabilistic models, e.g. with Direct distribution based on Consistent Blocks Algorithm, entails large run times. Hence, parallel platforms such as GPUs have been employed to speedup the simulation. In 2012, the first GPU simulator of PDP systems was presented. However, it was able to run only randomly generated PDP systems. In this paper, we present current updates made on this simulator, involving an input modu le for binary files and an output module for CSV files. Finally, the simulator has been experimentally validated with a real ecosystem model, and its performance has been tested with two high-end GPUs: Tesla C1060 and K40. 相似文献
3.
A. Ritacco R. Adam A. Adane P. Ade P. André A. Beelen B. Belier A. Benoît A. Bideaud N. Billot O. Bourrion M. Calvo A. Catalano G. Coiffard B. Comis A. D’Addabbo F.-X. Désert S. Doyle J. Goupy C. Kramer S. Leclercq J. F. Macías-Pérez J. Martino P. Mauskopf A. Maury F. Mayet A. Monfardini F. Pajot E. Pascale L. Perotto G. Pisano N. Ponthieu M. Rebolo-Iglesias V. Revéret L. Rodriguez G. Savini K. Schuster A. Sievers C. Thum S. Triqueneaux C. Tucker R. Zylka 《Journal of Low Temperature Physics》2016,184(3-4):724-732
4.
Ryan N. Smith Mac Schwager Stephen L. Smith Burton H. Jones Daniela Rus Gaurav S. Sukhatme 《野外机器人技术杂志》2011,28(5):714-741
Ocean processes are dynamic and complex and occur on multiple spatial and temporal scales. To obtain a synoptic view of such processes, ocean scientists collect data over long time periods. Historically, measurements were continually provided by fixed sensors, e.g., moorings, or gathered from ships. Recently, an increase in the utilization of autonomous underwater vehicles has enabled a more dynamic data acquisition approach. However, we still do not utilize the full capabilities of these vehicles. Here we present algorithms that produce persistent monitoring missions for underwater vehicles by balancing path following accuracy and sampling resolution for a given region of interest, which addresses a pressing need among ocean scientists to efficiently and effectively collect high‐value data. More specifically, this paper proposes a path planning algorithm and a speed control algorithm for underwater gliders, which together give informative trajectories for the glider to persistently monitor a patch of ocean. We optimize a cost function that blends two competing factors: maximize the information value along the path while minimizing deviation from the planned path due to ocean currents. Speed is controlled along the planned path by adjusting the pitch angle of the underwater glider, so that higher resolution samples are collected in areas of higher information value. The resulting paths are closed circuits that can be repeatedly traversed to collect long‐term ocean data in dynamic environments. The algorithms were tested during sea trials on an underwater glider operating off the coast of southern California, as well as in Monterey Bay, California. The experimental results show improvements in both data resolution and path reliability compared to previously executed sampling paths used in the respective regions. © 2011 Wiley Periodicals, Inc. 相似文献
5.
Jesús P. Mena-Chalco Ives Macêdo Luiz Velho Roberto M. Cesar Jr. 《The Visual computer》2009,25(10):899-909
In this paper, we present a 3D face photography system based on a facial expression training dataset, composed of both facial range images (3D geometry) and facial texture (2D photography). The proposed system allows one to obtain a 3D geometry representation of a given face provided as a 2D photography, which undergoes a series of transformations through the texture and geometry spaces estimated. In the training phase of the system, the facial landmarks are obtained by an active shape model (ASM) extracted from the 2D gray-level photography. Principal components analysis (PCA) is then used to represent the face dataset, thus defining an orthonormal basis of texture and another of geometry. In the reconstruction phase, an input is given by a face image to which the ASM is matched. The extracted facial landmarks and the face image are fed to the PCA basis transform, and a 3D version of the 2D input image is built. Experimental tests using a new dataset of 70 facial expressions belonging to ten subjects as training set show rapid reconstructed 3D faces which maintain spatial coherence similar to the human perception, thus corroborating the efficiency and the applicability of the proposed system. 相似文献
6.
7.
João Paulo Gois Diogo Fernando Trevisan Harlen Costa Batagelo Ives Macêdo 《The Visual computer》2013,29(6-8):651-661
In this work we investigate a generalized interpolation approach using radial basis functions to reconstruct implicit surfaces from polygonal meshes. With this method, the user can define with great flexibility three sets of constraint interpolants: points, normals, and tangents; allowing to balance computational complexity, precision, and feature modeling. Furthermore, this flexibility makes possible to avoid untrustworthy information, such as normals estimated on triangles with bad aspect ratio. We present results of the method for applications related to the problem of modeling 2D curves from polygons and 3D surfaces from polygonal meshes. We also apply the method to problems involving subdivision surfaces and front-tracking of moving boundaries. Finally, as our technique generalizes the recently proposed HRBF Implicits technique, comparisons with this approach are also conducted. 相似文献
8.
C. Macías P. Lavela G. Rasines M. C. Zafra J. L. Tirado C. O. Ania 《Journal of Applied Electrochemistry》2014,44(8):963-976
Three-activated carbon aerogels were synthesized by CO2 activation of the materials prepared by the polycondensation of resorcinol and formaldehyde mixtures followed by supercritical drying. The obtained carbon aerogels were characterized and used as electrode materials for the electrosorption of sodium phosphate and nitrate. X-ray diffraction and Raman spectroscopy showed the dependence of the structural ordering of the aerogels with the resorcinol/catalyst ratio and the extent of activation. The electrosorption capacitance evaluated by cyclic voltammetry revealed large values for the activated samples containing a large contribution of mesopores, regardless the electrolyte salt. Due to an adequate combination of chemical and porous features, the desalting capacity of the activated carbon aerogel electrodes exceeded that of the as-prepared materials. The evaluation of the kinetic properties by chronocoulometric relaxation and impedance spectroscopy showed a decrease of time constant and resistances for highly mesoporous activated samples. A high deionization capacity and fast electrode discharge was detected for the deionization of sodium nitrate on the highly mesoporous activated aerogel. Data also showed the efficient electrosorption of ionic species on consecutive charge/discharge cycles, confirming the stability of the aerogel electrodes at the high applied potentials. 相似文献
9.
The sulfur blooms on surface of rubber compounds cause loss of the needed tack for formation of multiply articles like tires. Although insoluble sulfur can be used to mitigate this problem, it is expensive to manufacture with a complex and hazardous process. This work examines an alternative approach that involves microencapsulation of soluble sulfur in alginate-based matrix. The formulations and procedures are developed and evaluated. Alginate crosslinking time, controlled temperature change (e.g., from 10 to 36°C), and the drying method were found to be critical to achieving high encapsulation efficiencies. The higher temperature (36°C) helped with the mass transfer limited removal of CS2 used for dissolving sulfur, and treatment of crosslinked beads with oil prior to air-drying improved sulfur encapsulation. Formulated beads had higher than 65% sulfur content (>80%, oil-free basis) with almost 90% of the beads being <150 μm. The process parameters can be adjusted to make even smaller beads. 相似文献
10.
J Delgado JA Pineda JA Gallardo M Leal J Macías A Sánchez-Quijano E Lissen 《Canadian Metallurgical Quarterly》1998,110(4):125-127
BACKGROUND: In recent years there has been a change in the opportunistic diseases incidence in HIV-infected patients. The change could be related to the use antiviral therapy and chemoprophylaxis strategies. The aim of the present study was to evaluate if medical intervention is able to modificate the clinical presentation of AIDS and the CD4+ lymphocyte counts at time of AIDS diagnosis. PATIENTS AND METHODS: The first AIDS-defining condition and the CD4+ count at time of AIDS diagnosis were analyzed in 95 HIV-infected patients who developed an AIDS-defining disease since April 1989 until March 1996, retrospectively reviewed. Patients who had been previously followed at an AIDS Unit were compared with those who had not. RESULTS: The frequency of Pneumocystis carinii pneumonia as the first AIDS-defining condition was lower in medically followed patients. Among this group, AIDS cases who received chemoprophylaxis with isoniazide showed a decrease in the rate of tuberculosis. No differences were found in CD4+ lymphocyte counts between both groups. CONCLUSIONS: As a result of medical intervention significant changes have occurred in the spectrum of initial AIDS-defining conditions in relation to medical intervention; a decrease in the frequency of Pneumocystis carinii pneumonia and tuberculosis have been found; however, the CD4+ lymphocyte counts at time of AIDS diagnosis are not modificated by medical intervention. 相似文献