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91.
A Faà di Bruno type Hopf algebra is developed for a group of integral operators known as Fliess operators, where operator composition is the group product. Such operators are normally written in terms of generating series over a noncommutative alphabet. Using a general series expansion for the antipode, an explicit formula for the generating series of the compositional inverse operator is derived. The result is applied to analytic nonlinear feedback systems to produce an explicit formula for the feedback product, that is, the generating series for the Fliess operator representation of the closed-loop system written in terms of the generating series of the Fliess operator component systems. This formula is employed to provide a proof that local convergence is preserved under feedback. 相似文献
92.
Adam C. Woodbury Jason F. Shepherd Matthew L. Staten Steven E. Benzley 《Engineering with Computers》2011,27(1):95-104
Finite element mesh adaptation methods can be used to improve the efficiency and accuracy of solutions to computational modeling
problems. In many applications involving hexahedral meshes, localized modifications which preserve a conforming all-hexahedral
mesh are desired. Effective hexahedral refinement methods that satisfy these criteria have recently become available; however,
due to hexahedral mesh topology constraints, little progress has been made in the area of hexahedral coarsening. This paper
presents a new method to locally coarsen conforming all-hexahedral meshes. The method works on both structured and unstructured
meshes and is not based on undoing previous refinement. Building upon recent developments in quadrilateral coarsening, the
method utilizes hexahedral sheet and column operations, including pillowing, column collapsing, and sheet extraction. A general
algorithm for automated coarsening is presented and examples of models that have been coarsened with this new algorithm are
shown. While results are promising, further work is needed to improve the automated process. 相似文献
93.
Mark Weiser described ubiquitous computing as “invisible, everywhere computing that does not live on a personal device of
any sort, but is in the woodwork everywhere”[1]. The EasyLiving project is concerned with development of an architecture and
technologies for ubiquitous computing environments that allow the dynamic aggregation of diverse I/O devices into a single
coherent user experience. Though the need for research in distributed computing, perception and interfaces is widely recognised,
the importance of an explicit geometric world model for enhancing the user’s experience of a ubiquitous computing system has
not been well-articulated. This paper describes three scenarios that benefit from geometric context and introduces the EasyLiving
Geometric Model. 相似文献
94.
This paper presents a structural application of a shape optimization method based on a Genetic Algorithm (GA). The method
produces a sequence of fixed-distance step-wise movements of the boundary nodes of a finite element model to derive optimal
shapes from an arbitrary initial design space. The GA is used to find the optimal or near-optimal combination of boundary
nodes to be moved for a given step movement. The GA uses both basic and advanced operators. For illustrative purposes, the
method has been applied to structural shape-optimization. The shape-optimization methodology presented allows local optimization,
where only crucial parts of a structure are optimized as well as global shape-optimization which involves finding the optimal
shape of the structure as a whole for a given environment as described by its loading and freedom conditions. Material can
be removed or added to reach the optimal shape. Two examples of structural shape optimization are included showing local and
global optimization through material removal and addition.
Received October 14, 1999 相似文献
95.
We describe a system which supports dynamic user interaction with multimedia information using content-based hypermedia navigation
techniques, specialising in a technique for navigation of musical content. The model combines the principles of open hypermedia, whereby hypermedia link information is maintained by a link service, with content-based retrieval techniques in which a database is queried based on a feature of the multimedia content; our approach could be described as
‘content-based retrieval of hypermedia links’. The experimental system focuses on temporal media and consists of a set of
component-based navigational hypermedia tools. We propose the use of melodic pitch contours in this context and we present
techniques for storing and querying contours, together with experimental results. Techniques for integrating the contour database
with open hypermedia systems are also discussed. 相似文献
96.
As a research paradigm, pattern analysis has been shown to be an effective tool for analyzing complex game situations in
both chess and go. We extend the prior pattern analysis research in chess to the domain of shogi. Shogi is computationally
more complex than chess and should realize greater benefits than the chess domain from pattern recognition and pattern exploitation
research. The IAM program, which has accurately predicted up to 28% of the moves for a specific chess player, is redesigned
to operate in the domain of shogi. Results similar to those achieved for the domain of chess are achieved in shogi.
Received 25 February 1999 / Revised 1 October 1999 / Accepted in revised form 2 February 2000 相似文献
97.
Koop D Scheidegger CE Callahan SP Freire J Silva CT 《IEEE transactions on visualization and computer graphics》2008,14(6):1691-1698
Building visualization and analysis pipelines is a large hurdle in the adoption of visualization and workflow systems by domain scientists. In this paper, we propose techniques to help users construct pipelines by consensus--automatically suggesting completions based on a database of previously created pipelines. In particular, we compute correspondences between existing pipeline subgraphs from the database, and use these to predict sets of likely pipeline additions to a given partial pipeline. By presenting these predictions in a carefully designed interface, users can create visualizations and other data products more efficiently because they can augment their normal work patterns with the suggested completions. We present an implementation of our technique in a publicly-available, open-source scientific workflow system and demonstrate efficiency gains in real-world situations. 相似文献
98.
99.
David-A. Mendels Emmelyn M. Graham Steven W. Magennis Anita C. Jones François Mendels 《Microfluidics and nanofluidics》2008,5(5):603-617
The development and adoption of lab-on-a-chip and micro-TAS (total analysis system) techniques requires not only the solving
of design and manufacturing issues, but also the introduction of reliable and quantitative methods of analysis. In this work,
two complementary tools are applied to the study of thermal and solutal transport in liquids. The experimental determination
of the concentration of water in a water–methanol mixture and of the temperature of water in a microfluidic T-mixer are achieved
by means of fluorescence lifetime imaging microscopy (FLIM). The results are compared to those of finite volume simulations
based on tabulated properties and well-established correlations for the fluid properties. The good correlation between experimental
and modelled results demonstrate without ambiguity that (1) the T-mixer is an adiabatic system within the conditions, fluids
and flow rates used in this study, (2) buoyancy effects influence the mixing of liquids of different densities at moderate
flow rates (Reynolds number Re ≪ 10−2), and (3) the combination of FLIM and computational fluid dynamics has the potential to be used to measure the thermal and
solutal diffusion coefficients of fluids for a range of temperatures and concentrations in one single experiment. As such,
it represents a first step towards the full-field monitoring of both the extent and the kinetics of a chemical reaction.
相似文献
David-A. MendelsEmail: |
100.
O'Riordan E Orlova TN Mendelev N Patschan D Kemp R Chander PN Hu R Hao G Gross SS Iozzo RV Delaney V Goligorsky MS 《Proteomics. Clinical applications》2008,2(7-8):1025-1035
The pathogenesis of progressive renal allograft injury, which is termed chronic allograft nephropathy (CAN), remains obscure and is currently defined by histology. Prospective protocol-biopsy trials have demonstrated that clinical and standard laboratory tests are insufficiently sensitive indicators of the development and progression of CAN. The study aim was to determine if CAN could be characterized by urinary proteomic data and identify the proteins associated with disease. The urinary proteome of 75 renal transplant recipients and 20 healthy volunteers was analyzed using surface enhanced laser desorption and ionization MS. Patients could be classified into subgroups with normal histology and Banff CAN grades 2-3 with a sensitivity of 86% and a specificity of 92% by applying the classification algorithm Adaboost to urinary proteomic data. Several urinary proteins associated with advanced CAN were identified including α1-microglobulin, β2-microglobulin, prealbumin, and endorepellin, the antiangiogenic C-terminal fragment of perlecan. Increased urinary endorepellin was confirmed by ELISA and increased tissue expression of the endorepellin/perlecan ratio by immunofluoresence analysis of renal biopsies. In conclusion, analysis of urinary proteomic data has further characterized the more severe CAN grades and identified urinary endorepellin, as a potential biomarker of advanced CAN. 相似文献