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971.
Specification of communicating processes: temporal logic versus refusals-based refinement 总被引:1,自引:1,他引:0
Gavin Lowe 《Formal Aspects of Computing》2008,20(3):277-294
In this paper we consider the relationship between refinement-oriented specification and specifications using a temporal logic.
We investigate the extent to which one can check whether a program in a process algebra, such as Communicating Sequential
Processes (CSP), satisfies a temporal logic specification using a refinement-based model checker, such as FDR. We consider
what atomic formulae are appropriate in a temporal logic for specifying communicating processes, in particular where one wants
to talk about the availability of events. We then show that, perhaps surprisingly, the standard stable failures model is not
adequate for capturing specifications in such a logic: instead the refusal traces model must be used. We formalise the logic
by giving it a semantics in this model. We show that the temporal operators eventually and until, and negation, cannot, in general, be tested for via simple refinement checks. For the remaining fragment of the logic, we
present a translation into simple refinement checks. Finally, we show that refusal traces equivalence is characterised by
a slightly augmented version of that fragment.
M. J. Butler 相似文献
972.
This work presents a driving system for a peristaltic micropump that is based on piezoelectric actuation. The effects of the
actuation sequence on pump performance are also considered. A valveless peristaltic micropump based on piezoelectric actuation
is designed and fabricated using microelectromechanical system technology. The pump has three parts––silicon, Pyrex glass
and commercially available bulk PZT (lead zirconate titanate) chips. The peristaltic micropump actuated by PZT chips comprises
three chambers that are in series. The driving system consists of an ATmega 8535 microprocessor, a high voltage power supply,
three differential amplifiers, a phase controller, an A/D converter, a 555 oscillator and an LCD module. It is supplied via
a 110 Vrms 60-Hz AC line and is programmable. The system can produce step-function signals with voltages of up to 100 Vpp and frequencies ranging from 10 Hz to 1 kHz, as the inputs for the pump. Fluid pumping with air is successfully demonstrated.
Additionally, 3-, 4- and 6-phase actuation sequences for the pump are designed and used to study the effects on pump performance,
as revealed by the flow rate and the displacement of a pump diaphragm. The experimental results show that the flow rate and
the displacement of the diaphragm actuated by the 4-phase sequence exceed those actuated by the 3- and 6-phase sequences.
A flow rate of 17.6 μl min−1 and a displacement of 2.91 μm (peak-to-peak) in 4-phase peristaltic motion are achieved at 100 Hz and 100 Vpp. The results demonstrate that the pump actuated in the 4-phase sequence is the most efficient. Consequently, the actuation
sequences can affect the pump performance. 相似文献
973.
J. Jiang Fanghua Mei W. J. Meng G. B. Sinclair Sunggook Park 《Microsystem Technologies》2008,14(6):815-819
For direct imprinting of metals, hard materials such as diamond and SiC have been used to construct mold inserts in preference
to Si, despite the ease in fabricating Si-based micro-/nano- scale structures. In this communication, we demonstrate that
micron scale Al structures can be replicated with good fidelity at room temperature by compression molding with Si inserts
without incurring insert damage. We further report on results of a finite element analysis of the mechanics of the molding
process. The finite element results provide some understanding of the observed lack of damage to the Si inserts. 相似文献
974.
This paper presents an innovative micro gyroscope design. The proposed tri-axis gyroscope possesses the capability of detecting
three-dimensional angular motions. The motion of each sensing element is, by elaborate mechanical design, restricted to move
in orthogonal direction to each other such that the measurements by high-resolution capacitors with signal processing circuits
are decoupled and precisely represent, to some extent, angular velocity components in three axes. The drive electrode comb
is used to constantly vibrate the proof mass in tangential direction by sinusoidal voltage. The signal bandwidth is increased
by distributed translational proof masses, placed ninety degree apart from each other. Each individual proof mass is designed
to move solely in radial direction so that superior mode matching can be achieved. In order to ensure better repeatability
and more reliability, the suspension flexures and damping effects are studied such that stress of the proposed micro gyroscope
is reduced but the span of angular displacements is increased. Owing to the complicated geometry of the suspension flexures,
finite element method (FEM) is employed to obtain more exact stiffness values and compared with theoretical analysis. The
dynamic model of the proposed gyroscope is established to include non-linear terms and embedded mechanical constraints. The
entire micro device can be produced merely by surface fabrication such that the mass production cost can be considered at
the design stage, while the resolution, bandwidth and decoupling capability of tri-axis detection are enhanced. 相似文献
975.
Lionel Buchaillot Olivier Millet Emmanuel Quévy Dominique Collard 《Microsystem Technologies》2008,14(1):69-78
The paper presents the snap-through phenomenon in the case of micro fabricated clamped-clamped buckled beam. This dynamic
post-buckling behavior is likely to occur in 3D microstructures when they are subjected to large vibration amplitudes. The
main difference between this work and previous studies is the MEMS specific beam dimension, especially the large initial deflection
of the buckled beam that involves the inversion of the two first resonance frequencies. The mathematical development allows
showing how the vibration amplitude of the supporting base affects the post-buckling dynamic behavior of the beam. For each
frequency, the limit between the stable behavior and the snap-through behavior is evaluated. Moreover, the effect of environment
is taken into account from the damping point of view. Samples are fabricated and the experiment is described. Measurements
are compared to the theoretical approach and the results are in good agreement with the proposed model. 相似文献
976.
Hyun Sup Lee Tai Hun Kwon Jong Hyun Kim Suk Sang Chang 《Microsystem Technologies》2008,14(8):1149-1155
The present study proposes a simple method to replicate nano/micro combined multiscale structures using an intermediate film
mold and anodic aluminum oxide (AAO) nanomold in hot embossing process. The proposed method is simply to add an intermediate
film mold with microscale thru-hole patterns to the ordinary mold system, on which nanostructures are patterned, in the hot
embossing process. The intermediate film mold is inserted between polymer substrate and AAO nanomold. During the hot embossing
process, the polymer first fills microscale thru-hole patterns in the intermediate film mold and subsequently fills nanopores
in AAO nanomold, resulting in the nano/micro combined structures. The intermediate film molds, which have microscale thru-hole
patterns were fabricated by micro-milling, laser ablation, etching methods and/or LIGA process. The nano/micro combined structures
were successfully replicated by the proposed method. 相似文献
977.
It is foreseen that more and more music objects in symbolic format and multimedia objects, such as audio, video, or lyrics,
integrated with symbolic music representation (SMR) will be published and broadcasted via the Internet. The SMRs of the flowing songs or multimedia objects will form a
music stream. Many interesting applications based on music streams, such as interactive music tutorials, distance music education, and
similar theme searching, make the research of content-based retrieval over music streams much important. We consider multiple
queries with error tolerances over music streams and address the issue of approximate matching in this environment. We propose
a novel approach to continuously process multiple queries over the music streams for finding all the music segments that are
similar to the queries. Our approach is based on the concept of n-grams, and two mechanisms are designed to reduce the heavy
computation of approximate matching. One mechanism uses the clustering of query n-grams to prune the query n-grams that are
irrelevant to the incoming data n-gram. The other mechanism records the data n-gram that matches a query n-gram as a partial
answer and incrementally merges the partial answers of the same query. We implement a prototype system for experiments in
which songs in the MIDI format are continuously broadcasted, and the user can specify musical segments as queries to monitor
the music streams. Experiment results show the effectiveness and efficiency of the proposed approach. 相似文献
978.
Collapse-free thermal bonding technique for large area microchambers in plastic lab-on-a-chip applications 总被引:1,自引:0,他引:1
Dong Sung Kim Hyun Sup Lee Jungyoup Han Se Hwan Lee Chong H. Ahn Tai Hun Kwon 《Microsystem Technologies》2008,14(2):179-184
Bonding is an essential step to form microchannels or microchambers in lab-on-a-chip applications. In this paper, we present
a novel plastic thermal bonding technique to seal and form large area microchambers (planar characteristic width and length
on the order of 1 mm and characteristic thickness on the order of 10–100 μm) without collapse by introducing a holed pressure
equalizing plate (HPEP) that includes holes of the same size and shape as the microchambers. To demonstrate the proposed technique,
two types of large area microchambers [(1) 20 × 10 mm and 40 μm thick and (2) 12 × 2.5 mm and 120 μm thick] with microchannels
were designed and replicated on plastic substrates by means of hot embossing and injection molding processes with prepared
two nickel mold inserts. The replicated large area microchambers as well as the microchannels in the plastic lab-on-a-chip
were successfully sealed (i.e., no leakage) and formed without any collapse by the proposed thermal bonding technique with
the help of the HPEP. 相似文献
979.
Scalable search-based image annotation 总被引:4,自引:0,他引:4
With the popularity of digital cameras, more and more people have accumulated considerable digital images on their personal
devices. As a result, there are increasing needs to effectively search these personal images. Automatic image annotation may
serve the goal, for the annotated keywords could facilitate the search processes. Although many image annotation methods have
been proposed in recent years, their effectiveness on arbitrary personal images is constrained by their limited scalability,
i.e. limited lexicon of small-scale training set. To be scalable, we propose a search-based image annotation algorithm that
is analogous to information retrieval. First, content-based image retrieval technology is used to retrieve a set of visually
similar images from a large-scale Web image set. Second, a text-based keyword search technique is used to obtain a ranked
list of candidate annotations for each retrieved image. Third, a fusion algorithm is used to combine the ranked lists into
a final candidate annotation list. Finally, the candidate annotations are re-ranked using Random Walk with Restarts and only
the top ones are reserved as the final annotations. The application of both efficient search techniques and Web-scale image
set guarantees the scalability of the proposed algorithm. Moreover, we provide an annotation rejection scheme to point out
the images that our annotation system cannot handle well. Experimental results on U. Washington dataset show not only the
effectiveness and efficiency of the proposed algorithm but also the advantage of image retrieval using annotation results
over that using visual features. 相似文献
980.
Image preview is a convenient way to browse large or multiple images on small displays. However, current signal-level image
resampling algorithms may remove many features of interest in the preview image. In this paper, we propose perceptual image
preview which retains more perceptual features such that users can inspect features of interest by viewing the preview image
only and without zooming in. This technology has two components, structure enhancement and perceptual feature visualization.
Structure enhancement enhances the image structure while suppressing subtle details using a gradient modulation method, thus
making the succedent perceptual features more apparent. For perceptual feature visualization, features of interest detected
in the picture is visualized on the structure enhanced preview image. We demonstrate with two examples of most commonly used image quality features, image blur and noise. The effectiveness of the proposed method is validated
by experimental results. 相似文献