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991.
Linguistic Problems with Requirements and Knowledge Elicitation 总被引:1,自引:0,他引:1
David C. Sutton 《Requirements Engineering》2000,5(2):114-124
Human and conversational aspects of requirements and knowledge identification are employed to show that requirements ‘engineering’
is not the same as civil engineering or scientific problem solving. Not only can requirements not be made fully explicit at
the start of a project, they cannot be made fully explicit at all. A need is identified to enhance computer-based information
systems (CBIS) development methods to accommodate: plurality of incommensurable perspectives, languages and agendas; dynamic
representations of system features that can be experienced rather than abstracted and forced into an abstract paper-based
representation; recognition that CBIS development is in general a continuous process where users changing their minds is a
natural and necessary indication or organisational vitality.
It is suggested that prototyping and rapid application development go some way to addressing these requirements but that
they require further development in the light of the theoretical light thrown on the nature of the problem. 相似文献
992.
X-machines were proposed by Holcombe as a possible specification language and since then a number of further investigations
have demonstrated that the model is intuitive and easy to use as well as general enough to cater for a wide range of applications.
In particular (generalised) stream X-machines have been found to be extremely useful as a specification method and most of
the theory developed so far has concentrated on this particular class of X-machines. Furthermore, a method for testing systems
specified by stream X-machines exists and is proved to detect all faults of the implementation provided that the system meets
certain initial requirements. However, this method can only be used to generate test sequences from deterministic X-machine
specifications. In this paper we present the theoretical basis for a method for generating test sets from non-deterministic
generalised stream X-machines.
Received November 1999 / Accepted in revised form September 2000 相似文献
993.
Easy-to-use audio/video authoring tools play a crucial role in moving multimedia software from research curiosity to mainstream
applications. However, research in multimedia authoring systems has rarely been documented in the literature. This paper describes
the design and implementation of an interactive video authoring system called Zodiac, which employs an innovative edit history abstraction to support several unique editing features not found in existing commercial
and research video editing systems. Zodiac provides users a conceptually clean and semantically powerful branching history model of edit operations to organize the authoring process, and to navigate among versions of authored documents. In addition,
by analyzing the edit history, Zodiac is able to reliably detect a composed video stream's shot and scene boundaries, which facilitates interactive video browsing.
Zodiac also features a video object annotation capability that allows users to associate annotations to moving objects in a video sequence. The annotations themselves could
be text, image, audio, or video. Zodiac is built on top of MMFS, a file system specifically designed for interactive multimedia development environments, and implements an internal buffer
manager that supports transparent lossless compression/decompression. Shot/scene detection, video object annotation, and buffer
management all exploit the edit history information for performance optimization. 相似文献
994.
Metrics for shot boundary detection in digital video sequences 总被引:5,自引:0,他引:5
The detection of shot boundaries in video sequences is an important task for generating indexed video databases. This paper
provides a comprehensive quantitative comparison of the metrics that have been applied to shot boundary detection. In addition,
several standardized statistical tests that have not been applied to this problem, as well as three new metrics, are considered.
A mathematical framework for quantitatively comparing metrics is supplied. Experimental results based on a video database
containing 39,000 frames are included. 相似文献
995.
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
996.
自然语言处理中的逻辑词 总被引:4,自引:0,他引:4
词是自然语言处理中最基本的单位,在当今知识表示领域,知识图作为自然语言理解的语义模型有其独到之处。本文从语言学和逻辑学的角度,首次提出并探讨了逻辑词研究逻辑词分类及如何用知识图表示各类逻辑词的结构。对自然语言处理中研究复句和篇章的理解提供了一种新的途径。 相似文献
997.
Ahmad H. Nasri 《The Visual computer》2000,16(1):3-14
C
0 (creases) or C
1 continuity across the interpolated curves. 相似文献
998.
Using vanishing points for camera calibration and coarse 3D reconstruction from a single image 总被引:5,自引:0,他引:5
In this paper, we show how to calibrate a camera and to recover the geometry and the photometry (textures) of objects from
a single image. The aim of this work is to make it possible walkthrough and augment reality in a 3D model reconstructed from
a single image. The calibration step does not need any calibration target and makes only four assumptions: (1) the single
image contains at least two vanishing points, (2) the length (in 3D space) of one line segment (for determining the translation
vector) in the image is known, (3) the principle point is the center of the image, and (4) the aspect ratio is fixed by the
user. Each vanishing point is determined from a set of parallel lines. These vanishing points help determine a 3D world coordinate
system R
o. After having computed the focal length, the rotation matrix and the translation vector are evaluated in turn for describing
the rigid motion between R
o and the camera coordinate system R
c. Next, the reconstruction step consists in placing, rotating, scaling, and translating a rectangular 3D box that must fit
at best with the potential objects within the scene as seen through the single image. With each face of a rectangular box,
a texture that may contain holes due to invisible parts of certain objects is assigned. We show how the textures are extracted
and how these holes are located and filled. Our method has been applied to various real images (pictures scanned from books,
photographs) and synthetic images. 相似文献
999.
The paper provides the results of preliminary research on the application of evolutionary computation to integrated structural
design in which a complex design support tool automatically conducts both conceptual and detailed design. In the paper, a
brief overview of the state of the art in evolutionary computation and its applications to structural design is provided.
Next, Inventor 2000 is described, a unique research and structural design tool developed by the authors at George Mason University that combines
an evolutionary computation component with a system for wind forces analysis, and a system for the analysis, design and optimisation
of steel structures. The paper also presents the results of four structural design experiments conducted with Inventor 2000.
The objective of experiments was to investigate various forms of evolutionary computation as applied to structure design.
Finally, the paper provides the initial research conclusions and recommendations for further research. 相似文献
1000.
Failure detection and consensus in the crash-recovery model 总被引:2,自引:0,他引:2
Summary. We study the problems of failure detection and consensus in asynchronous systems in which processes may crash and recover,
and links may lose messages. We first propose new failure detectors that are particularly suitable to the crash-recovery model.
We next determine under what conditions stable storage is necessary to solve consensus in this model. Using the new failure
detectors, we give two consensus algorithms that match these conditions: one requires stable storage and the other does not.
Both algorithms tolerate link failures and are particularly efficient in the runs that are most likely in practice – those
with no failures or failure detector mistakes. In such runs, consensus is achieved within time and with 4 n messages, where is the maximum message delay and n is the number of processes in the system.
Received: May 1998 / Accepted: November 1999 相似文献