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81.
82.
Alexandre N. Tuch Eva E. Presslaber Markus Stöcklin Klaus Opwis Javier A. Bargas-Avila 《International journal of human-computer studies》2012,70(11):794-811
This paper experimentally investigates the role of visual complexity (VC) and prototypicality (PT) as design factors of websites, shaping users' first impressions by means of two studies. In the first study, 119 screenshots of real websites varying in VC (low vs. medium vs. high) and PT (low vs. high) were rated on perceived aesthetics. Screenshot presentation time was varied as a between-subject factor (50 ms vs. 500 ms vs. 1000 ms). Results reveal that VC and PT affect participants' aesthetics ratings within the first 50 ms of exposure. In the second study presentation times were shortened to 17, 33 and 50 ms. Results suggest that VC and PT affect aesthetic perception even within 17 ms, though the effect of PT is less pronounced than the one of VC. With increasing presentation time the effect of PT becomes as influential as the VC effect. This supports the reasoning of the information-processing stage model of aesthetic processing (Leder et al., 2004), where VC is processed at an earlier stage than PT. Overall, websites with low VC and high PT were perceived as highly appealing. 相似文献
83.
Ogier Maitre Frédéric Krüger Stéphane Querry Nicolas Lachiche Pierre Collet 《Soft Computing - A Fusion of Foundations, Methodologies and Applications》2012,16(2):261-279
EASEA is a framework designed to help non-expert programmers to optimize their problems by evolutionary computation. It allows
to generate code targeted for standard CPU architectures, GPGPU-equipped machines as well as distributed memory clusters.
In this paper, EASEA is presented by its underlying algorithms and by some example problems. Achievable speedups are also
shown onto different NVIDIA GPGPUs cards for different optimization algorithm families. 相似文献
84.
A pattern is a model or a template used to summarize and describe the behavior (or the trend) of data having generally some recurrent events. Patterns have received a considerable attention in recent years and were widely studied in the data mining field. Various pattern mining approaches have been proposed and used for different applications such as network monitoring, moving object tracking, financial or medical data analysis, scientific data processing, etc. In these different contexts, discovered patterns were useful to detect anomalies, to predict data behavior (or trend) or, more generally, to simplify data processing or to improve system performance. However, to the best of our knowledge, patterns have never been used in the context of Web archiving. Web archiving is the process of continuously collecting and preserving portions of the World Wide Web for future generations. In this paper, we show how patterns of page changes can be useful tools to efficiently archive Websites. We first define our pattern model that describes the importance of page changes. Then, we present the strategy used to (i) extract the temporal evolution of page changes, (ii) discover patterns, to (iii) exploit them to improve Web archives. The archive of French public TV channels France Télévisions is chosen as a case study to validate our approach. Our experimental evaluation based on real Web pages shows the utility of patterns to improve archive quality and to optimize indexing or storing. 相似文献
85.
The solubility of aluminum in NaF-AlF3-Al2O3 melts with various additives was found to increase with increasing NaF/AlF3 molar ratio (CR) and increasing temperature and to decrease with additions of A12O3, CaF2, MgF2, and LiF to the melts. With the use of literature data for the activities of NaF and A1F3 in cryolitic melts, three dissolution reaction models were found to give a good fit to the experimental solubility data. According to the most probable of these models the total concentration of dissolved aluminum (aluminum and sodium species) is given by cAl = cNa(diss) + cAlF2- + cAl2F3- + cAl3F4- + cAl4F5- In NaF rich melts, aluminum will dominantly dissolve as sodium, while at cryolite ratios commonly used in aluminum electrowinning (CR = 2.25 to 2.7) the AlF -2 - -ion is the predominant dissolved metal species. Other species (A12F3 -, A13F4-, A14F5-) were found to be of some significance only in melts with high excess A1F3 (CR < 2). 相似文献
86.
A new high-order model for analysing distribution of temperature in periodic composites is proposed. The original scalar elliptic problem with Y-periodic coefficients (Y is a cube) is replaced with a vectorial elliptic problem of constant coefficients. The unknown fields are: the averaged distribution of temperature and the vector field which stands for perturbation of the temperature within the cells of periodicity. The recovery of temperature in the original composite is given by the approximation: 0(x)=0(x) +h
a
(x/)
a
(x) analogous with the first terms of the two-scale asymptotic expansion known from the homogenization theory. The functions h
are defined as approximations of the solutions to the basic cell problems. In contrast to the two-scale expansion the expression for satisfies the boundary condition. 相似文献
87.
Kähkönen E Nykyri E Ilmarinen R Ketola R Lusa S Nygård CH Suurnäkki T 《Applied ergonomics》1992,23(3):186-190
A study was made of the appraisers' effect on the estimation of metabolic rate with the Edholm scale and a table of the ISO 7243 heat stress standard. The appraisers, five experienced and five inexperienced persons, estimated the metabolic rate of three different work tasks from videotapes. Analysis of variance indicated significant ( [Formula: see text] ) differences in the appraisers' recordings of the activities. The appraisers were grouped according to the similarity of the estimated values they gave. The groups thus contained both experienced and inexperienced appraisers, and it was not possible to classify the appraisers into experienced and inexperienced groups according to their earlier experience. The metabolic rates according to the Edholm scale were higher than according to the ISO 7243 table. The differences in metabolic rates given by the individual observers varied from 38 to 118 W/m(2). The variations in the estimation of metabolic rates were greater when the Edholm scale was used. This variation caused considerable variation also in the predicted mean vote, PMV index. It is recommended that the appraisers be selected carefully, because it is not possible to know whether a randomly selected appraiser is an 'average' or an 'extreme' appraiser without a test. Before conducting extensive field surveys where several appraisers estimate the metabolic rates, it would be useful to arrange training in order to calibrate the levels of the Edholm scale as well as ISO method among the appraisers because training clearly unified the estimation. 相似文献
88.
In this paper we study small depth circuits that contain threshold gates (with or without weights) and parity gates. All circuits we consider are of polynomial size. We prove several results which complete the work on characterizing possible inclusions between many classes defined by small depth circuits. These results are the following:
相似文献
1. | A single threshold gate with weights cannot in general be replaced by a polynomial fan-in unweighted threshold gate of parity gates. |
2. | On the other hand it can be replaced by a depth 2 unweighted threshold circuit of polynomial size. An extension of this construction is used to prove that whatever can be computed by a depthd polynomial size threshold circuit with weights can be computed by a depthd+1 polynomial size unweighted threshold circuit, whered is an arbitrary fixed integer. |
3. | A polynomial fan-in threshold gate (with weights) of parity gates cannot in general be replaced by a depth 2 unweighted threshold circuit of polynomial size. |
89.
Experimental information and theoretical estimates for the enthalpy of formation at 298 K for the RM2 (whereM = Fe, Co,orNi andR = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu) lanthanide Laves phases with the MgCu2 (C15) structure are reviewed and discussed in the light of information on lattice parameters and atomic volume. The purpose of the present study is to analyze all the available experimental information on enthalpies of formation for transition-metal lanthanide Laves phases and then plot the data in order to reveal tendencies and allow reliable estimates of data that have not yet been measured. It is concluded that as the lanthanide atomic number increases the enthalpy of formation is almost constant or becomes slightly more negative. The accompanying volume contraction is slightly larger than expected from the lanthanide contraction, 7.6 %. From the so-called Gschneidner correlation one would have expected the contrary behavior, that is, that the bonding strength would become slightly lower when going from LaM2 to LuM2. An increase in the transition-metal atomic number has a stronger effect on the enthalpy of formation and atomic volume than an increase in the lanthanide atomic number. 相似文献
90.
The short-time hot-corrosion behavior of six industrial nickel-base superalloys was investigated with static deposits of Na2SO4 or NaCl or both in still air. The oxidation kinetics and scale morphologies were measured with traditional laboratory techniques-thermobalance, metallography, electron microprobe, and x-ray analyses. Susceptibility to hot corrosion was found to be correlated to the type of scale produced during simple oxidation. Alloys forming an A12O3 scale were found to be susceptible to Na2SO4 deposits, independent of their chromium content. The quantity of Na2SO4 deposit dictated the nature of the attack and, under certain conditions, the refractory element alloy additions appeared to play an essential role. Alloys containing Cr2O3 or TiO2 in the simple oxidation scale proved to be sensitive to NaCl attack. Again, the severity of the attack within the susceptible alloy group was not related to the chromium or titanium content. Although less intensive than the Na2SO4 -induced hot corrosion, NaCl contaminations provoked extensive spalling. All of the hotcorrosion types encountered in this study were interpreted in the light of existing theories.Supported by the Délégation Générale à la Recherche Scientifique et Technique. 相似文献