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   111249篇
  免费   9399篇
  国内免费   4196篇
电工技术   6035篇
技术理论   2篇
综合类   4690篇
化学工业   18289篇
金属工艺   5157篇
机械仪表   6855篇
建筑科学   5636篇
矿业工程   1985篇
能源动力   3846篇
轻工业   8425篇
水利工程   1744篇
石油天然气   2838篇
武器工业   776篇
无线电   17172篇
一般工业技术   16532篇
冶金工业   7828篇
原子能技术   1493篇
自动化技术   15541篇
  2024年   371篇
  2023年   1494篇
  2022年   2858篇
  2021年   4272篇
  2020年   3020篇
  2019年   2602篇
  2018年   3082篇
  2017年   3328篇
  2016年   3495篇
  2015年   4021篇
  2014年   5407篇
  2013年   7422篇
  2012年   7905篇
  2011年   8673篇
  2010年   7312篇
  2009年   7265篇
  2008年   6809篇
  2007年   6176篇
  2006年   5588篇
  2005年   4533篇
  2004年   3693篇
  2003年   3033篇
  2002年   2946篇
  2001年   2302篇
  2000年   1959篇
  1999年   1720篇
  1998年   2527篇
  1997年   1692篇
  1996年   1443篇
  1995年   1173篇
  1994年   868篇
  1993年   771篇
  1992年   573篇
  1991年   549篇
  1990年   467篇
  1989年   438篇
  1988年   344篇
  1987年   289篇
  1986年   271篇
  1985年   247篇
  1984年   215篇
  1983年   161篇
  1982年   162篇
  1981年   140篇
  1980年   148篇
  1979年   114篇
  1978年   102篇
  1977年   134篇
  1976年   179篇
  1975年   85篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
环氧化SBS胶粘剂的研制   总被引:8,自引:4,他引:8  
研究了环氧化SBS橡胶胶粘剂的合成及应用。试验结果表明环氧化SBS胶粘剂在粘接极性材料时的性能要优于SBS胶粘剂。  相似文献   
992.
为解决长江高填方护岸深厚覆盖层地基的抗滑稳定问题,采用振冲置换法对地基进行加固处理。计算分析表明,振冲碎石桩处理范围、桩间距、桩长等参数应结合地形、地质条件进行设计,振冲置换法与其他地基处理方式进行有机结合能够取得更好的处理效果;护岸地基通过振冲置换处理后,抗滑稳定性能够满足规范要求。采用振冲碎石桩对软弱地基进行置换形成复合地基,能够有效解决地基砂土液化问题、承载力问题及抗剪强度问题。  相似文献   
993.
胡波 《江苏化工》1997,(5):40-42
介绍了一套新型造气污水处理装置,该装置具有处理工艺流程合理,设备布置紧凑,装置自动化运行的特点,造气污水经处理后重复循环使用,污泥送沸腾炉作燃料燃烧,实现了污水零排放的目的。  相似文献   
994.
In order to investigate the effect of mixing ratio of bituminous coal to blended coal on the enhancement of combustion efficiency, combustion experiments of blended coal with anthracite and bituminous are done in a laboratory scale fluidized bed combustor (10.8 cm ID and 170 cm height). The gross heating values of anthracite and bituminous coal used in this study are 2,810 cal/g and 6,572 cal/g, respectively. Experimental parameters are fuel feed rate, superficial gas velocity and mixing ratio of bituminous coal to blended coal. The combustion efficiency increases with the mixing ratio of bituminous coal due to the lower unburned carbon losses and higher burning velocity of bituminous coal. The rate of combustion in the combustor was increased with mixing ratio resulted from a higher burning velocity of bituminous coal. The measured combustion efficiency experimentally is about 3.5-12.4% higher than that of the calculated value based on the individual combustion of anthracite and bituminous coal under the same operating conditions. The optimum mixing ratio (MR) of bituminous coal determined is around 0.75 in this study. This paper is dedicated to Professor Dong Sup Doh on the occasion of his retirement from Korea University.  相似文献   
995.
A surface diffusion mocel with diffusional interference has been presented for the analysis of multicomponent adsorption of phenols by activated carbon. Surface diffusion coefficients for multicomponent adsorptions were estimated from the relationship between. the surface diffusion coefficient of each species and the surface coverage. The diffusional interference coefficients, Wij, was determined from experimental counter-adsorption data. The numerical values of Wij were in the range of 0.4–0.9, which show that the introduction of diffusional interference is necessary to analyze multicomponent counter-adsorptions properly. The proposed model successfully simulates the behaviour of phenols-activated carbon system in a batch adsorber.  相似文献   
996.
The purpose of this study was to investigate the physiological and subjective responses of the European, Japanese (JPN) and US firefighters' helmet, gloves and boots for international standardisation. Three experimental conditions were evaluated (clothing mass: 9.4, 8.2 and 10.1 kg for the three conditions, respectively) at the air temperature of 32°C and 60% relative humidity. The results showed that there was no significant difference among the three conditions in oxygen consumption, heart rate, total sweat rate, rectal temperature and mean skin temperature, whereas peripheral temperatures and subjective perceptions were lower in the JPN condition than in the other conditions (P < 0.05). These results indicate that a 0.5-kg reduction in helmet mass and a 1.1-kg reduction in boot mass during exercise resulted in a significant decrease in head and leg temperatures and subjective perceptions, while a 1.9-kg reduction in total clothing mass had insignificant influences on the metabolic burden and overall body temperature.  相似文献   
997.
We propose a face detection method based on skin color likelihood via a boosting algorithm which emphasizes skin color information while deemphasizing non-skin color information. A stochastic model is adapted to compute the similarity between a color region and the skin color. Both Haar-like features and Local Binary Pattern (LBP) features are utilized to build a cascaded classifier. The boosted classifier is implemented based on skin color emphasis to localize the face region from a color image. Based on our experiments, the proposed method shows good tolerance to face pose variation and complex background with significant improvements over classical boosting-based classifiers in terms of total error rate performance.  相似文献   
998.
Visual tracking techniques based on stereo endoscope are developed to measure tissue motion in robot-assisted minimally invasive surgery. However, accurate 3D tracking of tissue surfaces remains challenging due to complicated deformation, poor imaging conditions, specular reflections and other dynamic effects during surgery. This study employs a robust and efficient 3D tracking scheme with two independent recursive processes, namely kernel-based inter-frame motion estimation and model-based intra-frame 3D matching. In the first process, target region is represented in joint spatial-color space for robust estimation. By defining a probabilistic similarity measure, a mean-shift-based iterative algorithm is derived for location of the target region in a new image. In the second process, the thin-plate spline model is used to fit the 3D shape of tissue surfaces around the target region. An iterative algorithm based on an efficient second-order minimization technique is derived to compute optimal model parameters. The two processes can be computed in parallel. Their outputs are combined to recover 3D information about the target region. The performance of the proposed method is validated using phantom heart videos and in vivo videos acquired by the daVinci®daVinci® surgical robotic platform and a synthesized data set with known ground truth.  相似文献   
999.
Handling occlusion is a very challenging problem in object detection. This paper presents a method of learning a hierarchical model for X-to-X occlusion-free object detection (e.g., car-to-car and person-to-person occlusions in our experiments). The proposed method is motivated by an intuitive coupling-and-decoupling strategy. In the learning stage, the pair of occluding X?s (e.g., car pairs or person pairs) is represented directly and jointly by a hierarchical And–Or directed acyclic graph (AOG) which accounts for the statistically significant co-occurrence (i.e., coupling). The structure and the parameters of the AOG are learned using the latent structural SVM (LSSVM) framework. In detection, a dynamic programming (DP) algorithm is utilized to find the best parse trees for all sliding windows with detection scores being greater than the learned threshold. Then, the two single X?s are decoupled from the declared detections of X-to-X occluding pairs together with some non-maximum suppression (NMS) post-processing. In experiments, our method is tested on both a roadside-car dataset collected by ourselves (which will be released with this paper) and two public person datasets, the MPII-2Person dataset and the TUD-Crossing dataset. Our method is compared with state-of-the-art deformable part-based methods, and obtains comparable or better detection performance.  相似文献   
1000.
Nowadays, customer orders with high product variety in small quantities are often received and requested for timely delivery. However, the order-picking process is a labour-intensive and costly activity to handle those small orders separately. In such cases, small orders are often grouped into batches so that two or more orders can be served at once to increase the picking efficiency and thus reduce the travel distance. In this paper, an order-picking operations system (OPOS) is proposed to assist the formulation of an order-picking plan and batch-handling sequence. The study integrates a mathematical model and fuzzy logic technique to divide the receiving orders into batches and prioritise the batch-handling sequence for picking, respectively. Through the proposed system, the order-picking process can be managed as batches with common picking locations to minimise the travel distance, and the batch-picking sequence can be determined as well. To demonstrate the use of the system, a case study in a third-party logistics warehouse is presented, and the result shows that both the order-picking activity and labour utilisation can be better organised.  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