全文获取类型
收费全文 | 12776篇 |
免费 | 966篇 |
国内免费 | 26篇 |
专业分类
电工技术 | 176篇 |
综合类 | 12篇 |
化学工业 | 3062篇 |
金属工艺 | 402篇 |
机械仪表 | 737篇 |
建筑科学 | 257篇 |
矿业工程 | 3篇 |
能源动力 | 646篇 |
轻工业 | 1106篇 |
水利工程 | 35篇 |
石油天然气 | 20篇 |
武器工业 | 1篇 |
无线电 | 2279篇 |
一般工业技术 | 2779篇 |
冶金工业 | 690篇 |
原子能技术 | 177篇 |
自动化技术 | 1386篇 |
出版年
2024年 | 15篇 |
2023年 | 154篇 |
2022年 | 212篇 |
2021年 | 393篇 |
2020年 | 303篇 |
2019年 | 332篇 |
2018年 | 408篇 |
2017年 | 469篇 |
2016年 | 462篇 |
2015年 | 456篇 |
2014年 | 636篇 |
2013年 | 898篇 |
2012年 | 906篇 |
2011年 | 1078篇 |
2010年 | 738篇 |
2009年 | 744篇 |
2008年 | 718篇 |
2007年 | 537篇 |
2006年 | 453篇 |
2005年 | 428篇 |
2004年 | 382篇 |
2003年 | 370篇 |
2002年 | 327篇 |
2001年 | 276篇 |
2000年 | 251篇 |
1999年 | 224篇 |
1998年 | 315篇 |
1997年 | 206篇 |
1996年 | 192篇 |
1995年 | 136篇 |
1994年 | 110篇 |
1993年 | 90篇 |
1992年 | 69篇 |
1991年 | 62篇 |
1990年 | 52篇 |
1989年 | 56篇 |
1988年 | 43篇 |
1987年 | 50篇 |
1986年 | 31篇 |
1985年 | 30篇 |
1984年 | 26篇 |
1983年 | 18篇 |
1982年 | 7篇 |
1981年 | 7篇 |
1980年 | 13篇 |
1978年 | 13篇 |
1977年 | 14篇 |
1976年 | 16篇 |
1974年 | 9篇 |
1972年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
Lee Jae-Gu Choi Kyung-Chan Yeon Seung-Ho Kim Jeong Won Ko Young-Woong 《Multimedia Tools and Applications》2017,76(23):25477-25494
Multimedia Tools and Applications - In digital pathology, image similarity algorithms are used to find cancer in tissue cells from medical images. However, it is very difficult to apply image... 相似文献
162.
Stability of neutral stochastic switched time delay systems: An average dwell time approach 下载免费PDF全文
This paper considers a class of stochastic systems referred to as stochastic switched systems of neutral type with time‐varying delay, which combines switched systems with neutral stochastic systems. The systems consist of subsystems of two forms: (i) only stable subsystems and (ii) both stable subsystems and unstable subsystems. By establishing an integral inequality, the exponential stability in pth(p≥1)‐moment for such systems with only stable subsystems is first considered. Then, by using an average dwell time approach, the exponential stability in pth(p≥1)‐moment for the second form is addressed. An important finding of this study is that when the average dwell time is chosen to be sufficiently large and the total activation time of unstable subsystems is relatively small compared with that of stable subsystems, the exponential stability in pth(p≥1)‐moment for such systems can be guaranteed. Two major advantages of these new results are that the differentiability or continuity of the delay function is not required compared with the existing results in the literature, and the proposed approaches can be used to consider the case when the neutral item and the stochastic perturbation are simultaneously presented. An example is provided to verify the effectiveness and potential of the theoretic results obtained. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
163.
Byung Chul Kim Duhwan Mun Soonhung Han Michael J. Pratt 《Computer aided design》2011,43(12):1717-1728
Procedural models have the advantage of being easy to edit simply by changing the values of the parameters of their constructional operations. Such models are said to embody design intent, in the sense that modifications to them conform to the method of creation used by their original creator. They also comply with any constraints implied by the particular constructional operations used. This paper introduces the development and standardization process of the ISO 10303-112 specification and describes the concept of procedural 2D modeling, a method of representing procedural 2D CAD models in STEP in harmony with other STEP resources. The feasibility of procedural 2D modeling commands for the exchange of procedurally represented 2D CAD model data is demonstrated through an experiment where procedural 2D CAD model data in neutral form generated with an in-house 2D modeling system are translated to and modified in a commercial 3D mechanical CAD system. 相似文献
164.
Won Tae Lee Jae Wook Lee Hyeon Yong Jang Seoung Jae Im SeGi Yu Jong Min Kim 《Journal of the Society for Information Display》2001,9(1):35-40
A new protecting layer, a LaF3‐coated MgO layer, in color AC‐plasma‐display panels (PDPs) was studied in order to overcome the weakness of the conventional single MgO protecting layer. The material characteristics of the new layer were examined by using variations in the deposition process. The display characteristics were also examined by implementing their processes to actual PDPs. It was demonstrated that this method is effective in lowering the firing and sustaining voltages of PDPs and enhancing the brightness of the panel as well. 相似文献
165.
Embedded systems such as PVR, set-top box, HDTV put unique demand on I/O subsystem design. Underlying software, particularly
file system, needs to be elaborately designed so that it can meet tight constraints of consumer electronics platform: performance,
price, reliability, and etc. In this work, we develop state-of-art file system elaborately tailored for A/V workload. There
are two design objectives in our file system: performance and support for logical level abstraction. For performance, we develop
a number of novel features: extent based allocation, single level file structure with block index augmentation scheme, aggressive
free block allocation to minimize disk fragmentation, elaborate file system meta data layout, separation of name space data
and file data and etc. HERMES enables the user to view file as a collection of semantic units (frame or audio samples). HERMES
file system encompasses most of state-of-the-art file system technologies published in preceding works. Via extensive physical
experiment, we verify that HERMES file system successfully addresses the original issues: good scalability, predictable I/O
latency (minimizing variability in I/O latency), efficient disk head movement and etc. This is the result of harmonious effort
of large I/O size, aggressive free block allocation algorithm, data block placement strategy, file organization, layout of
HERMES file system and etc. The result of performance experiments indicate that HERMES file system prototype successfully
meets the file system constraints for high volume and high bandwidth multimedia application. HERMES file system exhibits superior
performance to EXT2 file system (Linux) and XFS file system (SGI).
相似文献
Youjip WonEmail: |
166.
This paper proposes a probabilistic variant of the SOM-kMER (Self Organising Map-kernel-based Maximum Entropy learning Rule)
model for data classification. The classifier, known as pSOM-kMER (probabilistic SOM-kMER), is able to operate in a probabilistic
environment and to implement the principles of statistical decision theory in undertaking classification problems. A distinctive
feature of pSOM-kMER is its ability in revealing the underlying structure of data. In addition, the Receptive Field (RF) regions
generated can be used for variable kernel and non-parametric density estimation. Empirical evaluation using benchmark datasets
shows that pSOM-kMER is able to achieve good performance as compared with those from a number of machine learning systems.
The applicability of the proposed model as a useful data classifier is also demonstrated with a real-world medical data classification
problem. 相似文献
167.
Batch Nearest Neighbor Search for Video Retrieval 总被引:2,自引:0,他引:2
Jie Shao Zi Huang Heng Tao Shen Xiaofang Zhou Ee-Peng Lim Yijun Li 《Multimedia, IEEE Transactions on》2008,10(3):409-420
To retrieve similar videos to a query clip from a large database, each video is often represented by a sequence of high- dimensional feature vectors. Typically, given a query video containing m feature vectors, an independent nearest neighbor (NN) search for each feature vector is often first performed. After completing all the NN searches, an overall similarity is then computed, i.e., a single content-based video retrieval usually involves m individual NN searches. Since normally nearby feature vectors in a video are similar, a large number of expensive random disk accesses are expected to repeatedly occur, which crucially affects the overall query performance. Batch nearest neighbor (BNN) search is stated as a batch operation that performs a number of individual NN searches. This paper presents a novel approach towards efficient high-dimensional BNN search called dynamic query ordering (DQO) for advanced optimizations of both I/O and CPU costs. Observing the overlapped candidates (or search space) of a pervious query may help to further reduce the candidate sets of subsequent queries, DQO aims at progressively finding a query order such that the common candidates among queries are fully utilized to maximally reduce the total number of candidates. Modelling the candidate set relationship of queries by a candidate overlapping graph (COG), DQO iteratively selects the next query to be executed based on its estimated pruning power to the rest of queries with the dynamically updated COG. Extensive experiments are conducted on real video datasets and show the significance of our BNN query processing strategy. 相似文献
168.
Leveraging online communities in fostering adaptive schools 总被引:1,自引:0,他引:1
David Hung Kenneth Y. T. Lim Der-Thanq Victor Chen Thiam Seng Koh 《International Journal of Computer-Supported Collaborative Learning》2008,3(4):373-386
There has long been a call for schools to prepare students for the twenty-first century where skills and dispositions differ
significantly from much of what has historically characterized formal education. The knowledge based economy calls for policy
and pedagogical efforts that would transform schools. Schools are to foster communities of learners. This paper suggests that
para-communities may be points of leverage in the fostering of adaptive schools. A critical analysis is done on the differences
between para-communities (such as online communities) and schools; and an argument is made that they each serve differing
goals and should be left distinct because they achieve different societal and economic demands. 相似文献
169.
Rachel Edita Oñate Roxas Allan Borra Charibeth Ko Cheng Nathalie Rose Lim Ethel Chuajoy Ong Michelle Wendy Tan 《Language Resources and Evaluation》2008,42(2):183-195
In this paper, we present the building of various language resources for a multi-engine bi-directional English-Filipino Machine
Translation (MT) system. Since linguistics information on Philippine languages are available, but as of yet, the focus has
been on theoretical linguistics and little is done on the computational aspects of these languages, attempts are reported
here on the manual construction of these language resources such as the grammar, lexicon, morphological information, and the
corpora which were literally built from almost non-existent digital forms. Due to the inherent difficulties of manual construction,
we also discuss our experiments on various technologies for automatic extraction of these resources to handle the intricacies
of the Filipino language, designed with the intention of using them for the MT system. To implement the different MT engines
and to ensure the improvement of translation quality, other language tools (such as the morphological analyzer and generator,
and the part of speech tagger) were developed. 相似文献
170.
Restoring warped document images through 3D shape modeling 总被引:2,自引:0,他引:2
Tan CL Zhang L Zhang Z Xia T 《IEEE transactions on pattern analysis and machine intelligence》2006,28(2):195-208
Scanning a document page from a thick bound volume often results in two kinds of distortions in the scanned image, i.e., shade along the "spine" of the book and warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. From a technical point of view, this shape from shading (SFS) problem in real-world environments is characterized by 1) a proximal and moving light source, 2) Lambertian reflection, 3) nonuniform albedo distribution, and 4) document skew. Taking all these factors into account, we first build practical models (consisting of a 3D geometric model and a 3D optical model) for the practical scanning conditions to reconstruct the 3D shape of the book surface. We next restore the scanned document image using this shape based on deshading and dewarping models. Finally, we evaluate the restoration results by comparing our estimated surface shape with the real shape as well as the OCR performance on original and restored document images. The results show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly. 相似文献