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551.
Raman Kumar Goyal Jaskirat Singh Nidhi Kalra Anshu Parashar Gagan Singla Sakshi Kaushal 《计算机系统科学与工程》2022,41(1):157-170
This paper proposes anoptimal fuzzy-based model for obtaining crisp priorities for Fuzzy-AHP comparison matrices. Crisp judgments cannot be given for real-life situations, as most of these include some level of fuzziness and complexity. In these situations, judgments are represented by the set of fuzzy numbers. Most of the fuzzy optimization models derive crisp priorities for judgments represented with Triangular Fuzzy Numbers (TFNs) only. They do not work for other types of Triangular Shaped Fuzzy Numbers (TSFNs) and Trapezoidal Fuzzy Numbers (TrFNs). To overcome this problem, a sum of squared error (SSE) based optimization model is proposed. Unlike some other methods, the proposed model derives crisp weights from all of the above-mentioned fuzzy judgments. A fuzzy number is simulated using the Monte Carlo method. A threshold-based constraint is also applied to minimize the deviation from the initial judgments. Genetic Algorithm (GA) is used to solve the optimization model. We have also conducted casestudiesto show the proposed approach’s advantages over the existingmethods. Results show that the proposed model outperforms other models to minimize SSE and deviation from initial judgments. Thus, the proposed model can be applied in various real time scenarios as it can reduce the SSE value upto 29% compared to the existing studies. 相似文献
552.
Review of background subtraction methods using Gaussian mixture model for video surveillance systems
Foreground detection or moving object detection is a fundamental and critical task in video surveillance systems. Background subtraction using Gaussian Mixture Model (GMM) is a widely used approach for foreground detection. Many improvements have been proposed over the original GMM developed by Stauffer and Grimson (IEEE Computer Society conference on computer vision and pattern recognition, vol 2, Los Alamitos, pp 246–252, 1999. doi: 10.1109/CVPR.1999.784637) to accommodate various challenges experienced in video surveillance systems. This paper presents a review of various background subtraction algorithms based on GMM and compares them on the basis of quantitative evaluation metrics. Their performance analysis is also presented to determine the most appropriate background subtraction algorithm for the specific application or scenario of video surveillance systems. 相似文献
553.
The performance of Calpine's Geysers steam field from startup in 1960 to 2008 is described in this paper. Since October 2003, Calpine has received approximately 482 L/s of tertiary-treated reclaimed water from the City of Santa Rosa. To accommodate and derive benefit from this water, Calpine has converted 20 wells (ten producers, six shut-in, two observation, and two suspended wells) to high-rate injection service. Additional nine wells were also converted to low-rate injectors that receive 12.6 L/s or less. Annual recovery factors (i.e., fieldwide increase in annual steam production divided by annual injection) for the first 5 years of Santa Rosa Geysers Recharge Project (SRGRP) operation have been estimated at 17.6%, 26.1%, 37.1%, 39% and 44.6%, respectively; reasonably close to or slightly higher than the values, predicted prior to SRGRP startup. Using a revised definition that includes the amount of un-boiled water in the reservoir, the annual recovery factors turn out to be 17.6%, 16.1%, 14.6%, 12.4% and 12.2% from year one through year five. Improvements in the wellfield, water injection, and power plant modifications from January 1995 through December 2008 are also discussed in this paper. 相似文献
554.
Raj K. Goyal Rajesh K. Vishwakarma & Onkar D. Wanjari 《International Journal of Food Science & Technology》2009,44(1):36-41
In this study, hulling efficiency and hulling losses were optimised for pigeonpea. Effects of hulling time, moisture content and cottonseed oil as pre-milling agent were studied and optimised using response surface methodology. A quadratic model satisfactorily described the hulling efficiency with an R 2 value of 0.93. It predicted maximum dehulling efficiency of 89.98% at 9.82% moisture content (wet basis), 12.05-s time of hulling and 0.28% cottonseed oil treatment. Linear model developed for hulling loss showed significant effect of time of hulling whereas effect of oil treatment and moisture content were non-significant. The model predicted hulling loss of 2.92% on optimum conditions. The results of the model were validated experimentally and were within the range. 相似文献
555.
I. B. Kazatchkov S. G. Hatzikiriakos N. Bohnet S. K. Goyal 《Polymer Engineering and Science》1999,39(4):804-815
The rheological and processing behavior (melt fracture performance) of linear lowdensity polyethylenes (LLDPEs) is studied as a function of both the weight average molecular weight (Mw) and its distribution (MWD). A number of LLDPE resins having different molecular characteristics were tested, with essentially one characteristic (Mw or MWD) changing at a time. The first series of resins consisted of nine samples having a wide range of polydispersities (3.3–12.7) and nearly constant Mw and short chain branching. The second series had six resins with varying Mw (51,000–110,000) but fixed MWD (about 4). The influence of Mw and MWD on the viscosity profiles, linear viscoelastic moduli as expressed by means of a discrete spectrum of relaxation times, extrudate swell, and melt fracture behavior for these resins is reported. Correlations between the molecular characteristics of the resins and their rheological and processing behavior are also reported. It is found that for a given molecular weight, the optimum melt fracture performance is obtained at a specific polydispersity value, and it is characterized by a minimum relaxation time for the resin defined in terms of recoverable shear. 相似文献
556.
Kalyanaraman S. Jain R. Fahmy S. Goyal R. Vandalore B. 《Networking, IEEE/ACM Transactions on》2000,8(1):87-98
This paper describes the “explicit rate indication for congestion avoidance” (ERICA) scheme for rate-based feedback from asynchronous transfer mode (ATM) switches. In ERICA, the switches monitor their load on each link and determine a load factor, the available capacity, and the number of currently active virtual channels. This information is used to advise the sources about the rates at which they should transmit. The algorithm is designed to achieve high link utilization with low delays and fast transient response. It is also fair and robust to measurement errors caused by the variations in ABR demand and capacity. We present performance analysis of the scheme using both analytical arguments and simulation results. The scheme is being considered for implementation by several ATM switch manufacturers 相似文献
557.
High performance nanocomposites were prepared by incorporating 0–12 vol.% nano-sized (39 nm) Al2O3 particles into PEEK matrix using compression molding. The microhardness and dynamic mechanical properties of the nanocomposites increase with increasing Al2O3 content. The wear resistance of the nanocomposites evaluated at a sliding speed of 1.0 m/s and nominal pressure from 0.5 MPa to 1.25 MPa under dry sliding conditions was improved more than threefold at 0.8 vol.% Al2O3 content. However, the wear resistance of the nanocomposites containing above 1.67 vol.% Al2O3 was deteriorated, despite their higher hardness and stiffness as compared to that of nanocomposites containing lower Al2O3 content. The surface roughness of the wear track formed over the countersurface increases with increasing Al2O3 content. The coefficient of friction of nanocomposites was higher than that of pure PEEK. SEM and optical microscopy have shown that wear of pure PEEK occurs by the mechanism of adhesion mainly, whereas of nanocomposites by microploughing and abrasion. Energy dispersive spectrometry (EDS) shows that Fe and alloying elements of countersurface transfer to the wear debris at higher Al2O3 content. 相似文献
558.
Boufounos P. Oppenheim A.V. Goyal V.K. 《Signal Processing, IEEE Transactions on》2008,56(3):1071-1082
In a variety of signal processing and communications contexts, erasures occur inadvertently or can be intentionally introduced as part of a data reduction strategy. This paper discusses causal compensation for erasures in frame representations of signals. The approach described assumes linear synthesis of the signal using a prespecified frame but no specific generation mechanism for the coefficients. Under this assumption, it is demonstrated that erasures can be compensated for using low-complexity causal systems. If the transmitter is aware of the occurrence of the erasure, an optimal compensation is to project the erasure error to the remaining coefficients. It is demonstrated that the same compensation can be executed using a transmitter/receiver combination in which the transmitter is not aware of the erasure occurrence. The transmitter precompensates using projections, as if assuming erasures will occur. The receiver undoes the compensation for the coefficients that have not been erased, thus maintaining the compensation only of the erased coefficients. The stability of the resulting systems is explored, and stability conditions are derived. It is shown that stability for any erasure pattern can be enforced by optimizing a constrained quadratic program at the system design stage. The paper concludes with examples and simulations that verify the theoretical results and illustrate key issues in the algorithms. 相似文献
559.
Assessment of Creep Deformation,Damage, and Rupture Life of 304HCu Austenitic Stainless Steel Under Multiaxial State of Stress 总被引:1,自引:0,他引:1
K. C. Sahoo Sunil Goyal P. Parameswaran S. Ravi K. Laha 《Metallurgical and Materials Transactions A》2018,49(3):881-898
The role of the multiaxial state of stress on creep deformation and rupture behavior of 304HCu austenitic stainless steel was assessed by performing creep rupture tests on both smooth and notched specimens of the steel. The multiaxial state of stress was introduced by incorporating circumferential U-notches of different root radii ranging from 0.25 to 5.00 mm on the smooth specimens of the steel. Creep tests were carried out at 973 K over the stress range of 140 to 220 MPa. In the presence of notch, the creep rupture strength of the steel was found to increase with the associated decrease in rupture ductility. Over the investigated stress range and notch sharpness, the strengthening was found to increase drastically with notch sharpness and tended toward saturation. The fractographic studies revealed the mixed mode of failure consisting of transgranular dimples and intergranular creep cavitation for shallow notches, whereas the failure was predominantly intergranular for relatively sharper notches. Detailed finite element analysis of stress distribution across the notch throat plane on creep exposure was carried out to assess the creep failure of the material in the presence of notch. The reduction in von-Mises stress across the notch throat plane, which was greater for sharper notches, increased the creep rupture strength of the material. The variation in fracture behavior of the material in the presence of notch was elucidated based on the von-Mises, maximum principal, and hydrostatic stresses. Electron backscatter diffraction analysis of creep strain distribution across the notch revealed localized creep straining at the notch root for sharper notches. A master curve for predicting creep rupture life under the multiaxial state of stress was generated considering the representative stress having contributions from both the von-Mises and principal stress components of the stress field in the notch throat plane. Rupture ductility was also predicted based on the multiaxial state of stress. 相似文献
560.
ABSTRACT: Lycopene is the principal pigment of the carotenoids naturally found in tomatoes and is important not only because of the color it imparts but also because of the recognized health benefits associated with its presence. Red tomatoes typically contain about 95% of their lycopene as the all‐trans isomer, the most stable form. In tangerine tomatoes, on the other hand, the lycopene is present as tetra‐cis‐lycopene, a geometric isomer of all‐trans lycopene. Lycopene is a major component found in blood serum. This carotenoid has been extensively studied for its antioxidant and cancer‐preventing properties. Prevention of heart disease has been shown to be another antioxidant role played by lycopene because it reduces the accumulation of platelets that eventually lead to blood clots, heart attacks, and strokes. In contrast to many other food phytonutrients whose effects have only been studied in animals, lycopene from tomatoes has been repeatedly studied in humans and found to be protective against several cancers, which now include colorectal, prostate, breast, lung, and pancreatic cancers. This review outlines the background information dealing with lycopene and presents the most comprehensive and current understanding of its potential functional role in human health. 相似文献