全文获取类型
收费全文 | 31275篇 |
免费 | 2676篇 |
国内免费 | 1359篇 |
专业分类
电工技术 | 1792篇 |
技术理论 | 5篇 |
综合类 | 1862篇 |
化学工业 | 5426篇 |
金属工艺 | 1444篇 |
机械仪表 | 1842篇 |
建筑科学 | 2298篇 |
矿业工程 | 916篇 |
能源动力 | 794篇 |
轻工业 | 2318篇 |
水利工程 | 546篇 |
石油天然气 | 1669篇 |
武器工业 | 241篇 |
无线电 | 3871篇 |
一般工业技术 | 3966篇 |
冶金工业 | 1486篇 |
原子能技术 | 292篇 |
自动化技术 | 4542篇 |
出版年
2024年 | 136篇 |
2023年 | 576篇 |
2022年 | 1045篇 |
2021年 | 1420篇 |
2020年 | 1046篇 |
2019年 | 874篇 |
2018年 | 962篇 |
2017年 | 1049篇 |
2016年 | 967篇 |
2015年 | 1302篇 |
2014年 | 1573篇 |
2013年 | 1977篇 |
2012年 | 1970篇 |
2011年 | 2179篇 |
2010年 | 1777篇 |
2009年 | 1700篇 |
2008年 | 1692篇 |
2007年 | 1573篇 |
2006年 | 1651篇 |
2005年 | 1413篇 |
2004年 | 920篇 |
2003年 | 850篇 |
2002年 | 727篇 |
2001年 | 622篇 |
2000年 | 709篇 |
1999年 | 759篇 |
1998年 | 667篇 |
1997年 | 564篇 |
1996年 | 536篇 |
1995年 | 389篇 |
1994年 | 354篇 |
1993年 | 260篇 |
1992年 | 216篇 |
1991年 | 161篇 |
1990年 | 146篇 |
1989年 | 109篇 |
1988年 | 87篇 |
1987年 | 60篇 |
1986年 | 47篇 |
1985年 | 43篇 |
1984年 | 30篇 |
1983年 | 20篇 |
1982年 | 35篇 |
1981年 | 24篇 |
1980年 | 17篇 |
1979年 | 11篇 |
1978年 | 11篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1971年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
91.
为了构建自供能式磁流变阻尼器内部实时状态监测传感系统,本文介绍了一种针对磁流变阻尼器内部流体能的能量采集装置。该装置被安装于磁流变阻尼器活塞顶端并为检测阻尼器内部工作参数的无线传感模块1供电。根据能量守恒定律,推导出磁流变阻尼器中磁流变液流动能的理论模型。通过实验测试分析了在不同的外界激励下能量采集装置的工作情况,证明了采集的电能随着活塞的运动频率增加而增加,而与磁流变阻尼器的磁流变特性没有明显的关系。测试表明利用此装置能较好的采集到来自于磁流变阻尼器内部流体流动产生的能量,为无线传感模块供电。 相似文献
92.
Journal of Porous Materials - Nitrogen and oxygen co-doped hierarchical porous carbons (NOPCs) is prepared by the pyrolysis of polyethylene glycol-200 (PEG) and triazine carbon forming agent (CFA)... 相似文献
93.
Cinkilic Emre Moodispaw Michael Zhang Jianyue Miao Jiashi Luo Alan A. 《Metallurgical and Materials Transactions A》2022,53(8):2861-2873
Metallurgical and Materials Transactions A - The use of secondary aluminum for structural components in the automotive industry is limited by the high Fe contents in recycled alloys which often... 相似文献
94.
95.
96.
Nickel electrodes were prepared by electrodeposition in electrolytes of various anionic compositions. The deposition conditions and bath types were evaluated with special emphasis on the electrocatalytic properties for the oxygen evolution reaction (OER). Electrochemical characterizations in a 5 mol/L KOH solution at 25°C showed that the electrode deposited from the chloride bath, having a low Tafel slope of 50 mV/dec and an overpotential of 396 mV at 100 mA/cm2, is the most catalytically active among electrodes prepared in electrolytes of various anionic compositions. The electrode activity for the OER is related to the real surface areas, which depend on the anion compositions in the deposition bath and the deposition conditions. 相似文献
97.
A polygon P admits a sweep if two mobile guards can detect an unpredictable, moving target inside P , no matter how fast the target moves. Two guards move on the polygon boundary and are required to always be mutually visible. The objective of this study is to find an optimum sweep such that the sum of the distances travelled by the two guards in the sweep is minimized. We present an O(n2) time and O(n) space algorithm for optimizing this metric, where n is the number of vertices of the given polygon. Our result is obtained by reducing this problem to finding a shortest path between two nodes in a graph of size O(n). 相似文献
98.
The oxygen evolution reaction (OER) is the anodic reaction in several industrial electrolytic processes. The objective of this work was to develop a new electrocatalytic material for long-lasting and economical high performance electrodes. New electrodes were prepared by electrodeposition of nickel, nickel-ruthenium and nickel-iridium alloys. They were then activated by anodic polarization at 100 mA cm–2 to form an oxide layer. The electrocatalytic activity was characterized for the OER in 5M KOH solution. The results show that nickel-iridium alloys provide greater electrocatalytic activity for the OER and better corrosion resistance than nickel-ruthenium in alkaline solution. The effects of transition elements on improving the performance of the nickel electrode are then discussed.Notation
b
Tafel slope
-
i
ex
exchange current density
-
i
dp
electrodeposition current density
-
i
OER
oxygen evolution reaction current density
-
C
dl
double-layer capacity
- o2
oxygen overpotential 相似文献
99.
The “hardness” components in sea water can be considerably reduced by means of a new economical fixed bed technique called “Reciprocating Flow Ion Exchange”, when used in conjunction with a closed cycle exchanger-evaporator system. Removal of 87.9% of the calcium and 54.5% of the magnesium in sea water has been obtained with an overall flow rate of 5.0 U. S. g. p. m./sq. ft. Results from bench scale and a 5,000 g. p. d. pilot plant were identical. The virtually continuous cyclic steady-state process requires a small amount of exchanger (0.5 to 2% of the usual ion exchange methods, such as conventional fixed beds or fluidized beds). The effects of variation in operating parameters are discussed. 相似文献
100.
Dalibor Petković Shahaboddin Shamshirband Hadi Saboohi Tan Fong Ang Nor Badrul Anuar Nenad D. Pavlović 《Applied Intelligence》2014,41(3):887-896
The prerequisite for new versatile grippers is the capability to locate and perceive protests in their surroundings. It is realized that automated controllers are profoundly nonlinear frameworks, and a faultless numerical model is hard to get, in this way making it troublesome to control utilizing tried and true procedure. Here, a design of an adaptive compliant gripper is presented. This design of the gripper has embedded sensors as part of its structure. The use of embedded sensors in a robot gripper gives the control system the ability to control input displacement of the gripper and to recognize specific shapes of the grasping objects. Since the conventional control strategy is a very challenging task, soft computing based controllers are considered as potential candidates for such an application. In this study, the polynomial and radial basis function (RBF) are applied as the kernel function of Support Vector Regression (SVR) to estimate and predict optimal inputs displacement of the gripper according to experimental tests and shapes of grasping objects. Instead of minimizing the observed training error, SVR poly and SVR rbf attempt to minimize the generalization error bound so as to achieve generalized performance. The experimental results show that an improvement in predictive accuracy and capability of generalization can be achieved by the SVR approach compared to other soft computing methodology. 相似文献