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   1748篇
  免费   82篇
  国内免费   4篇
电工技术   38篇
综合类   3篇
化学工业   364篇
金属工艺   42篇
机械仪表   60篇
建筑科学   26篇
矿业工程   3篇
能源动力   112篇
轻工业   107篇
水利工程   18篇
石油天然气   2篇
无线电   166篇
一般工业技术   455篇
冶金工业   178篇
原子能技术   8篇
自动化技术   252篇
  2024年   10篇
  2023年   30篇
  2022年   59篇
  2021年   80篇
  2020年   70篇
  2019年   73篇
  2018年   80篇
  2017年   90篇
  2016年   84篇
  2015年   53篇
  2014年   72篇
  2013年   128篇
  2012年   73篇
  2011年   88篇
  2010年   92篇
  2009年   81篇
  2008年   48篇
  2007年   47篇
  2006年   38篇
  2005年   34篇
  2004年   22篇
  2003年   37篇
  2002年   34篇
  2001年   20篇
  2000年   18篇
  1999年   16篇
  1998年   44篇
  1997年   32篇
  1996年   20篇
  1995年   11篇
  1994年   13篇
  1993年   23篇
  1992年   11篇
  1991年   5篇
  1990年   13篇
  1989年   13篇
  1988年   14篇
  1987年   17篇
  1986年   6篇
  1985年   22篇
  1984年   11篇
  1983年   11篇
  1982年   11篇
  1981年   13篇
  1980年   19篇
  1979年   11篇
  1977年   4篇
  1976年   12篇
  1974年   4篇
  1973年   3篇
排序方式: 共有1834条查询结果,搜索用时 531 毫秒
1.
2.
Neural Computing and Applications - The advanced high-end gadgets and sophisticated machines require effective mechanism of transferring heat away from the sources. In a large number of...  相似文献   
3.
4.
5.
A dynamic model for computer simulation and control of steelmaking has been developed. It is essentially based on multicomponent mixed transport control theory with the incorporation of energy balance calculations. The model is applicable to both steelmaking in electric furnaces as well as in oxygen steelmaking converters. The adjustable parameters of the model for simulation of oxygen steelmaking are gas evolution rate (Gco). oxygen flux factor (Fo) and emulsification factor (EM). These simulation parameters, when combined with on-line measurement of off-gas composition and temperature, enable complete dynamic control of the process. The model developed is applied, as an example, to an industrially produced heat in a top blown oxygen steelmaking converter and the results of simulation are discussed.  相似文献   
6.
The present work investigates the efficacy and applicability of interior global orthogonal point collocation method to the axisymmetric nonlinear analysis of elastic circular plates and shallow spherical shells subjected to uniformly distributed transverse load. Spacewise discretisation has been carried out using a polynomial expansion with the zeros of a Chebyshev polynomial as collocation points. Timewise integration has been carried out with Newmark k-β scheme corresponding to average acceleration method. The static response and snap-through buckling results, as well as, the dynamic response and dynamic buckling results under a uniformly distributed step load have been obtained and found to agree closely with the available results.  相似文献   
7.
Support vector clustering involves three steps—solving an optimization problem, identification of clusters and tuning of hyper-parameters. In this paper, we introduce a pre-processing step that eliminates data points from the training data that are not crucial for clustering. Pre-processing is efficiently implemented using the R*-tree data structure. Experiments on real-world and synthetic datasets show that pre-processing drastically decreases the run-time of the clustering algorithm. Also, in many cases reduction in the number of support vectors is achieved. Further, we suggest an improvement for the step of identification of clusters.  相似文献   
8.
The nonsimilar and self-similar flows for the steady natural convection over a vertical heated surface in a saturated porous medium with mass transfer using non-Darcy model have been studied under boundary layer approximations. The differential equations governing both the nonsimilar and self-similar flows have been solved numerically using an implicit finite-difference scheme developed by Keller. The results indicate that both heat transfer and velocity field are appreciably affected by the modified Grashof number and mass transfer except that the effect of the modified Grashof number on the heat transfer for large suction is very small. It is found that the maximum velocity occurs at the wall and it increases as the modified Grashof number or injection increases.  相似文献   
9.
Static network-related system voltage stability margin (VSM) depends on the availability of reactive power to support the transport of real power from sources to sinks. Based on this premise, the total VAr loss is minimized in the unified OPF framework considering real and reactive power controllers, and its effect on VSM is studied. Studies are conducted on a three-bus system, the IEEE 30-bus system, and a 191-bus Indian electric power system, and their results are reported.  相似文献   
10.
Litchi (Litchi chinensis Sonn.) fruits are very susceptible to pericarp browning which adversely affects consumer acceptability even though the aril portion remains in excellent condition. Litchi arils (litchis) were treated with a solution containing 0–2% (w/v) calcium lactate (CL), 0–0.02% (w/v) 4‐hexyl resorcinol (4‐HR) and 1% potassium sorbate. The pH of solution was adjusted to 4.0 with citric acid. Treated litchis were packed in polystyrene trays, over‐wrapped with polypropylene film, vacuum‐packed (0, 47409.3, 94831.9 Pa) and stored at 4 ± 2 °C. Drip losses, pH, total soluble solids (TSS), sensory attributes and microbiological quality of stored samples were estimated. A four‐factor, three‐level experimental design (D6 Hokes design) with 19 experiments was chosen. Mathematical models were developed to analyse and predict the effect of CL, 4‐HR, in‐package vacuum and storage time on the responses. TSS, pH and sensory scores decreased significantly (P 0.01), whereas drip losses and microbial count increased significantly (P 0.01) with time. Drip loss was significantly (P 0.1) reduced by addition of CL. 4‐HR prevented browning and changes in colour score during storage were significantly less. Vacuum in packages exerted significant (P 0.01) effect over pH, TSS, sensory and microbiological qualities of minimally processed litchis.  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