首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2335篇
  免费   114篇
  国内免费   5篇
电工技术   19篇
综合类   1篇
化学工业   589篇
金属工艺   48篇
机械仪表   64篇
建筑科学   84篇
矿业工程   3篇
能源动力   69篇
轻工业   238篇
水利工程   16篇
石油天然气   6篇
武器工业   1篇
无线电   221篇
一般工业技术   430篇
冶金工业   217篇
原子能技术   17篇
自动化技术   431篇
  2023年   23篇
  2022年   54篇
  2021年   72篇
  2020年   60篇
  2019年   65篇
  2018年   64篇
  2017年   63篇
  2016年   62篇
  2015年   67篇
  2014年   89篇
  2013年   171篇
  2012年   132篇
  2011年   179篇
  2010年   130篇
  2009年   99篇
  2008年   145篇
  2007年   91篇
  2006年   92篇
  2005年   65篇
  2004年   63篇
  2003年   68篇
  2002年   59篇
  2001年   33篇
  2000年   20篇
  1999年   30篇
  1998年   83篇
  1997年   46篇
  1996年   43篇
  1995年   33篇
  1994年   34篇
  1993年   30篇
  1992年   16篇
  1991年   9篇
  1990年   13篇
  1989年   8篇
  1988年   13篇
  1987年   10篇
  1986年   16篇
  1985年   19篇
  1984年   9篇
  1983年   7篇
  1982年   5篇
  1981年   8篇
  1980年   9篇
  1979年   6篇
  1978年   5篇
  1977年   4篇
  1976年   8篇
  1974年   4篇
  1973年   8篇
排序方式: 共有2454条查询结果,搜索用时 31 毫秒
51.
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   
52.
Universal Access in the Information Society - Computational Thinking (CT) captures the mental processes used to model and solve problems using a computational processes. While often connected to...  相似文献   
53.
Real-Time Systems - Heterogeneous MPSoCs are being used more and more, from cellphones to critical embedded systems. Most of those systems offer heterogeneous sets of identical cores. In this...  相似文献   
54.
Nowadays, dietary assessment becomes the emerging system for evaluating the person’s food intake. In this paper, the multiple hypothesis image segmentation and feed-forward neural network classifier are proposed for dietary assessment to enhance the performance. Initially, the segmentation is applied to input image which is used to determine the regions where a particular food item is located using salient region detection, multi-scale segmentation, and fast rejection. Then, the significant feature of food items is extracted by the global feature and local feature extraction method. After the features are obtained, the classification is performed for each segmented region using feed-forward neural network model. Finally, the calorie value is computed with the aid of (i) food area volume and (ii) calorie and nutrition measure based on mass value. The outcome of the proposed method attains 96% of accuracy value which provides the better classification performance.  相似文献   
55.
This paper explores in detail, the microstructures and thermoelectric properties of Te-rich and Te-poor (Bi,Sb)2Te3 alloys. We show that tuning the composition of ternary Bi–Sb–Te type alloys allows us to synthesize a range of microstructures containing a primary solid solution of (Bi,Sb)2Te3 with varying amounts of Te solid solution or a (Bi,Sb)Te compound. Te exists as a constituent of the multilayer domain while (Bi,Sb)Te appears in the thin intercellular regions of the (Bi,Sb)2Te3 dendritic cells. The presence of Te imparts an n-type behavior to the composite while the (Bi,Sb)2Te3 with a small amount of (Bi,Sb)Te exhibits p-type properties. A maximum ZT value of ≈0.4 at 425 K was achieved, opening up the possibility of using these alloys for thermoelectric device applications.  相似文献   
56.
We present in this paper a model for indexing and querying web pages, based on the hierarchical decomposition of pages into blocks. Splitting up a page into blocks has several advantages in terms of page design, indexing and querying such as (i) blocks of a page most similar to a query may be returned instead of the page as a whole (ii) the importance of a block can be taken into account, as well as (iii) the permeability of the blocks to neighbor blocks: a block b is said to be permeable to a block b?? in the same page if b?? content (text, image, etc.) can be (partially) inherited by b upon indexing. An engine implementing this model is described including: the transformation of web pages into blocks hierarchies, the definition of a dedicated language to express indexing rules and the storage of indexed blocks into an XML repository. The model is assessed on a dataset of electronic news, and a dataset drawn from web pages of the ImagEval campaign where it improves by 16% the mean average precision of the baseline.  相似文献   
57.
The challenge of segmenting the moving object is harder when the background is dynamic and the camera used can change its zoom dynamically. Here, in this paper, we propose a method to detect and segment moving object from a dynamic background, which contains moving multiple-leaf doors. In addition, the proposed algorithm also takes care of dynamic zoom changes that can occur while shooting a scene. The proposed method uses background-rebuilding with discrete door’s position to tackle moving multiple-leaf door backgrounds and image feature comparison to tackle changes in zoom. The experiment results show satisfying segmentation results with high processing speed.  相似文献   
58.
We propose a generative model based method for recovering both the shape and the reflectance of the surface(s) of a scene from multiple images, assuming that illumination conditions and cameras calibration are known in advance. Based on a variational framework and via gradient descents, the algorithm minimizes simultaneously and consistently a global cost functional with respect to both shape and reflectance. The motivations for our approach are threefold. (1) Contrary to previous works which mainly consider specific individual scenarios, our method applies indiscriminately to a number of classical scenarios; in particular it works for classical stereovision, multiview photometric stereo and multiview shape from shading. It works with changing as well as static illumination. (2) Our approach naturally combines stereo, silhouette and shading cues in a single framework. (3) Moreover, unlike most previous methods dealing with only Lambertian surfaces, the proposed method considers general dichromatic surfaces. We verify the method using various synthetic and real data sets.  相似文献   
59.
The automatic compilation of bilingual lists of terms from specialized comparable corpora using lexical alignment has been successful for single-word terms (SWTs), but remains disappointing for multi-word terms (MWTs). The low frequency and the variability of the syntactic structures of MWTs in the source and the target languages are the main reported problems. This paper defines a general framework dedicated to the lexical alignment of MWTs from comparable corpora that includes a compositional translation process and the standard lexical context analysis. The compositional method which is based on the translation of lexical items being restrictive, we introduce an extended compositional method that bridges the gap between MWTs of different syntactic structures through morphological links. We experimented with the two compositional methods for the French–Japanese alignment task. The results show a significant improvement for the translation of MWTs and advocate further morphological analysis in lexical alignment.  相似文献   
60.
During the continuous casting of steel, several disturbances occur and affect all the parts of the caster, including the mould where the molten steel has to be stable for good quality of the final product. Especially at high casting velocities, the bulging generates important level fluctuations which cannot be efficiently rejected by the classical controllers. To address these problems, this paper proposes an architecture combining disturbances estimation and compensation techniques. It operates as an additional module and does not need any change of the main controller currently implemented. The entire structure has been tested successfully through several simulations and by means of intensive water model experiments.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号