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951.
This paper contributes an interpretation of Domberger's theory of The Contracting Organization for use in an IT outsourcing context, then presents a preliminary test of the validity of that theory using data from an Australian survey of 235 senior IT managers. Our conclusion is that Domberger's theory appears to be a useful lens for understanding IT outsourcing, and that further research using purpose-collected data is therefore warranted. Phrased differently, Domberger's four types of benefit of contracting – namely Specialization, Market Discipline, Flexibility, and Cost Savings – appear to be a good way of summarizing senior IT managers’ explanations of why their organizations chose to outsource IT. The paper also conducts a preliminary test of the extent to which these four factors explain the purchasing organization's satisfaction with IT outsourcing.  相似文献   
952.
953.
This paper investigates the tracking problem for a class of uncertain switched nonlinear delayed systems with nonstrict‐feedback form. To address this problem, by introducing a new common Lyapunov function (CLF), an adaptive neural network dynamic surface control is proposed. The state‐dependent switching rule is designed to orchestrate which subsystem is active at each time instance. In order to compensate unknown delay terms, an appropriate Lyapunov‐Krasovskii functional is considered in the constructing of the CLF. In addition, a novel switched neural network–based observer is constructed to estimate system states through the output signal. To maintain the tracking error performance within a predefined bound, a prescribed performance bound approach is employed. It is proved that by the proposed output‐feedback control, all the signals of the closed‐loop system are bounded under the switching law. Moreover, the transient and steady‐state tracking performance is guaranteed by the prescribed performance bound. Finally, the effectiveness of the proposed method is illustrated by two numerical and practical examples.  相似文献   
954.
We define a new mathematical model for the topological study of lattice height data. A discrete multivalued dynamical system framework is used to establish discrete analogies of a Morse function, its gradient field, and its stable and unstable manifolds in order to interpret functions numerically given on finite sets of pixels. We present efficient algorithms detecting critical components of a height function f and displaying connections between them by means of a graph, called the Morse connections graph whose nodes represent the critical components of f and edges show the existence of connecting trajectories between nodes. This graph encodes efficiently the topological structure of the data and makes it easy to manipulate for subsequent processing.
Anik TrahanEmail:
  相似文献   
955.
This article summarizes and scrutinizes the growth of the development of clinically relevant and psychometrically sound approaches for determining the clinical significance of treatment effects in mental health research by tracing its evolution, by examining modifications in the method, and by discussing representative applications. Future directions for this methodology are proposed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
956.
Data gathered from mothers on parenting and family climate when almost 1,000 children in the Dunedin, New Zealand, longitudinal study were 3, 5, 7, 9, 13, and 15 years of age were used to predict intergenerational relations between young adult children (age 26) and their middle-aged parents. Analyses focused on distinct developmental epochs revealed greater prediction from the middle-childhood and early-adolescent periods than from the early-childhood years; most indicated that more supportive family environments and child-rearing experiences in the family of origin forecasted more positive and less negative parent-child relationships (in terms of contact, closeness, conflict, reciprocal assistance) in young adulthood, though associations were modest in magnitude. Some evidence indicated that (modestly) deleterious effects on intergenerational relations of experiencing relatively unsupportive child-rearing environments in 1 but not 2 (of 3) developmental periods studied could be offset by relatively supportive family environments in the remaining developmental periods. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
957.
The current work is the first effort to show the capability of SnTe quantum dots (QDs) in as a quantum dots solar cell device, which work in visible-near-infrared (NIR) regions, and improvement of the solar cell parameters by Eu-doping. Undoped and Eu-doped SnTe QDs with different Eu concentration from 2 to 6% were synthesized by a co-precipitation method. X-ray diffraction patterns and transmission electron microscopy images indicated that, crystallite and particle size of the samples were decreased by increasing of Eu content. Fourier-transform infrared (FTIR) and Raman spectroscopy results revealed that some vibration modes were appeared and disappeared by Eu-doping. According to the photoluminescence (PL) results, PL intensity of the doped sample was enhanced significantly in the green region in comparison to the PL intensity of the undoped sample. Ultraviolet-visible-near infrared spectroscopy results indicated that the pristine and Eu(2%)-doped samples don’t have any absorption in the visible region, while, Eu(4% and 6%)-doped SnTe QDs showed a good absorption in this region. Photocurrent measurements showed that, unlike the pristine and Eu(2%)-doped QDs, Eu(4% and 6%)-doped SnTe QDs showed a high responsivity in the visible and NIR regions. Solar cell measurements showed that, solar cell parameters such as short current density (Jsc), open circuit voltage (Voc), conversion efficiency values (η), and fill factor (FF) were increased by Eu-doping.  相似文献   
958.
959.
Polymer additives are used to improve the properties of road bitumens including their oxidative resistance. However, their usage as anti-oxidative materials remains relatively unclear. This study aims to investigate the changes in the morphology and the rheological response of polymer modified bitumens used in road pavement construction caused by ageing. An elastomer (radial styrene butadiene styrene, SBS) and a plastomer (ethyl vinyl acetate, EVA) polymer were mixed with one base bitumen at three polymer concentrations. The bitumens were RTFO and PAV aged. The morphology of the bitumens was captured by fluorescence microscopy while the rheological properties were measured by means of the multiple stress creep and recovery (MSCR) test. The results show that the morphology of the SBS modified bitumen degrades with ageing as a function of polymer concentration and dispersion, with higher dispersion being more resistant. The morphology of the EVA modified bitumen has a low ageing susceptibility irrespective of polymer concentration. The MSCR response of EVA modified bitumens does not differ from that found for unmodified bitumen, where the hardening produces a decrease in the non-recoverable compliance. In the case of SBS modified bitumen, the degradation of the polymer backbone affects the bitumen hardening as much as the polymer phase dispersed and networked in the bitumen phase. Furthermore, in the case of the elastomer, the average percent recovery is in agreement with the variation of the morphology with ageing. Therefore, the use of the average percent recovery as a valuable rheological index of the integrity of the polymer network can be advocated.  相似文献   
960.
The fascinating properties of two dimensional (2D) crystals have gained increasing interest for many applications. The synthesis of a 2D silicon structure, namely silicene, is attracting great interest for possible development of next generation electronic devices. The main difficulty in working with silicene remains its strong tendency to oxidation when exposed to air as a consequence of its relatively highly buckled structure. In this work, we univocally identify the Raman mode of air-stable low-buckled silicene nanosheets synthesized on highly oriented pyrolytic graphite (HOPG) located at 542.5 cm?1. The main focus of this work is Raman spectroscopy and mapping analyses in combination with ab initio calculations. Scanning tunneling microscopy images reveal the presence of a patchwork of Si three-dimensional (3D) clusters and contiguous Si areas presenting a honeycomb atomic arrangement, rotated by 30° with respect to the HOPG substrate underneath, with a lattice parameter of 0.41 ± 0.02 nm and a buckling of the Si atoms of 0.05 nm. Raman analysis supports the co-existence of 3D silicon clusters and 2D silicene. The Raman shift of low-buckled silicene on an inert substrate has not been reported so far and it is completely different from the one calculated for free-standing silicene and the ones measured for silicene grown on Ag(111) surfaces. Our experimental results are perfectly reproduced by our ab initio calculations of deposited silicene nanosheets. This leads us to conclude that the precise value of the observed Raman shift crucially depends on the strain between the silicene and the HOPG substrate.
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