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111.
112.
Leandro C. Silva Valéria V. Murata Carla E. Hori Adilson J. Assis 《Optimization and Engineering》2010,11(3):441-458
In this work three mathematical models for methane steam reforming in membrane reactors were developed. The first one is a
steady state, non isothermal, non isobaric and one dimensional model derived from material and energy balances and validated
using experimental data from the literature. It is referred as full model. The influence of two different intrinsic kinetics
available, as well as, the influence of five important parameters on methane conversion (XCH4_{\mathrm{CH}_{4}}) and hydrogen recovery (YH2_{\mathrm{H}_{2}}) were parametrically evaluated through simulations. The second model, referred as meta-model, was obtained though the response
surface technique. This meta-model was included into a constrained optimization problem solved using NPSOL. The third model,
referred as a simplified model, takes into account only mass balances from the full model. Using this model, a gradient based
method (DIRCOL) was used to perform the optimization of the sum of methane conversion and hydrogen recovery. High methane
conversions and hydrogen recoveries were reached through these methodologies. 相似文献
113.
114.
Giovana O. Silva Edwin M.M. Ortega Gauss M. Cordeiro 《Computational statistics & data analysis》2009,53(12):4482-4489
A bathtub-shaped failure rate function is very useful in survival analysis and reliability studies. The well-known lifetime distributions do not have this property. For the first time, we propose a location-scale regression model based on the logarithm of an extended Weibull distribution which has the ability to deal with bathtub-shaped failure rate functions. We use the method of maximum likelihood to estimate the model parameters and some inferential procedures are presented. We reanalyze a real data set under the new model and the log-modified Weibull regression model. We perform a model check based on martingale-type residuals and generated envelopes and the statistics AIC and BIC to select appropriate models. 相似文献
115.
Detection and recognition of the level of congestion at an intersection is a very important problem and a valuable source of information in traffic management. Although it is just one of all the aspects that make up a traffic management system, it seems to be a crucial point for gathering information. In this paper, we present a technique based on a k-means clustering algorithm for classification, which has been already successfully used in a number of pattern recognition problems, namely: as an algorithm for face recognition problems and in a number of medical diagnosis problems and it compares very well with the state of the art techniques. 相似文献
116.
The author searched for empirically based theories and models with an interpersonal and relational focus. This search was conducted in spite of academic and professional psychology’s general avoidance of theory building coupled with an exaggerated reliance on empirical evidence, producing a chaotic proliferation of models unrelated to each other. Requirements for any theory are verifiability, applicability, redundancy, and fruitfulness. Many two-factor relational theories and models derive from the two assumptions of space and time. From these models and theories two stand out: attachment theory and relational competence theory (RCT). Both theories attempt to link heretofore separate fields: research and practice. The major asset of attachment theory has been a multitude of studies in the English-speaking world. The major shortcoming of RCT is that research to support the validity of its models has been conducted only in Italy. However, many test instruments, enrichment programs, and interactive practice exercises for some models of RCT are available in English. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
117.
118.
Moacir Fernandes Ferreira Júnior Elaine Angélica Ribeiro Mundim Guimes Rodrigues Filho Carla da Silva Meireles Daniel Alves Cerqueira Rosana Maria Nascimento de Assunção Marcos Marcolin Mara Zeni 《Polymer Bulletin》2011,66(3):377-389
Cellulose, obtained both from sugarcane bagasse and mango seeds, was used for synthesizing cellulose acetate in order to produce
asymmetric membranes. These were compared to membranes of commercial cellulose acetate (Rhodia). All produced membranes were
asymmetric, characterized by the presence of a dense skin and a porous support. Differences regarding the morphology of the
surfaces as well as of the porous support can be noticed. Scanning Electron Microscopy (SEM) showed that the morphology of
the superficial layer, responsible for transport, depends on the different lignin content of the starting material and also
on the viscosity average molecular weight of the cellulose acetates produced from sugarcane bagasse, mango seed, and Rhodia’s
commercial cellulose acetate. 相似文献
119.
José Robinson-Duggon Francisco Pérez-Mora Luciano Dibona-Villanueva Denis Fuentealba 《Israel journal of chemistry》2018,58(3-4):199-214
Cucurbit[n]urils (CB[n]s) have emerged as potential candidates for drug delivery in several areas due to their strong binding interactions and low toxicity. More recently, their benefits for a type of cancer treatment termed Photodynamic Therapy (PDT) have been recognized. The outcomes of this therapy rely on better drug delivery strategies and improving overall photoactivity of the drugs, which is where CB[n]s could have a strong impact. The effects of these molecular containers on photoactivity are discussed and new interesting work is highlighted. 相似文献
120.
Countercurrent supercritical fluid extraction of grape-spirit 总被引:1,自引:0,他引:1
A procedure for the recovery of aromatic extracts from raw grape-spirit (alcohol strength 73 vol.%) by means of a countercurrent supercritical fluid extraction (CC-SFE) on a pilot plant scale is presented. The effect of the solvent-to-feed ratio at 7, 8, 10, and 20 kgCO2/kgFeed on the extraction of flavor compounds, operating at constant pressure of 100 bar and extraction temperature of 50 °C have been studied. Increasing the solvent-to-feed ratio from 7 to 20 kgCO2/kgFeed, the total volatile compounds yield decreases from 64 to 5% and that of ethanol from 85 to 49%. The highest concentration of volatile compounds has been obtained at 7 and 8 kgCO2/kgFeed solvent-to-feed ratio. Mixtures containing grape-spirit (alcohol strength 40 vol.%) added with 30% (v/v) of different extracts have been tested and judged by a panel. Sensory evaluation indicated as preferred the mixtures added with the extracts obtained at lowest solvent-to-feed ratio. 相似文献