全文获取类型
收费全文 | 3140篇 |
免费 | 124篇 |
国内免费 | 18篇 |
专业分类
电工技术 | 58篇 |
综合类 | 16篇 |
化学工业 | 691篇 |
金属工艺 | 48篇 |
机械仪表 | 68篇 |
建筑科学 | 46篇 |
矿业工程 | 3篇 |
能源动力 | 154篇 |
轻工业 | 289篇 |
水利工程 | 18篇 |
石油天然气 | 14篇 |
无线电 | 330篇 |
一般工业技术 | 641篇 |
冶金工业 | 467篇 |
原子能技术 | 27篇 |
自动化技术 | 412篇 |
出版年
2023年 | 33篇 |
2022年 | 55篇 |
2021年 | 123篇 |
2020年 | 82篇 |
2019年 | 92篇 |
2018年 | 102篇 |
2017年 | 92篇 |
2016年 | 110篇 |
2015年 | 57篇 |
2014年 | 105篇 |
2013年 | 180篇 |
2012年 | 140篇 |
2011年 | 159篇 |
2010年 | 121篇 |
2009年 | 112篇 |
2008年 | 128篇 |
2007年 | 119篇 |
2006年 | 98篇 |
2005年 | 94篇 |
2004年 | 60篇 |
2003年 | 58篇 |
2002年 | 48篇 |
2001年 | 29篇 |
2000年 | 43篇 |
1999年 | 40篇 |
1998年 | 163篇 |
1997年 | 104篇 |
1996年 | 90篇 |
1995年 | 58篇 |
1994年 | 64篇 |
1993年 | 54篇 |
1992年 | 38篇 |
1991年 | 33篇 |
1990年 | 23篇 |
1989年 | 24篇 |
1988年 | 25篇 |
1987年 | 16篇 |
1986年 | 21篇 |
1985年 | 26篇 |
1984年 | 32篇 |
1983年 | 14篇 |
1982年 | 18篇 |
1981年 | 17篇 |
1980年 | 19篇 |
1978年 | 17篇 |
1977年 | 17篇 |
1976年 | 31篇 |
1975年 | 15篇 |
1974年 | 20篇 |
1972年 | 12篇 |
排序方式: 共有3282条查询结果,搜索用时 703 毫秒
71.
Huang Tianpeng Huang Deqing Wang Zhikai Dai Xi Shah Awais 《International Journal of Control, Automation and Systems》2021,19(2):698-711
International Journal of Control, Automation and Systems - This paper aims to provide a generic robust controller that is able to manipulate all kinds of quadrotor unmanned aerial vehicle (UAV)... 相似文献
72.
Nouman Ali Shah Yue Ren Ri-Tong Lan Jia-Cheng Lv Rizwan M. Gul Peng-Fei Tan Shishu Huang Lin Tan Jia-Zhuang Xu Zhong-Ming Li 《应用聚合物科学杂志》2021,138(43):51261
Highly crosslinked ultrahigh molecular weight polyethylene (UHMWPE) stabilized by vitamin E (VE) is widely applied in artificial joints as the bearings. Despite the approval, there is a discord that VE lowers the crosslinking efficiency, limiting its use at high concentration. In this work, we aim to obtain highly crosslinked and oxidation resistant UHMWPE through the conjunction of tea polyphenol and chemical crosslinking. We hypothesized that highly incorporated tea polyphenol with multiple reactive sites can ameliorate crosslinking efficiency of chemical crosslinked UHMWPE in comparison to VE. Epigallocatechin gallate (EGCG) as representative tea polyphenol was incorporated into UHMWPE at high concentration (2–8 wt%), followed by chemical crosslinking with 2 wt% organic peroxide. Unlike VE/UHMWPE blends as the control, chemical crosslinking achieved an increasing trend in crosslink density of EGCG/UHMWPE blends with increasing antioxidant concentration. High concentration of EGCG also enhanced the oxidation stability of UHMWPE. Intriguingly, EGCG endowed UHMWPE with an excellent antimicrobial property, which was inefficient in VE/UHMWPE. Cell viability was hardly affected by the high loaded antioxidant and peroxide. The chemically crosslinked UHMWPE blended with EGCG is proved to be a reasonable, cost effective and realistic alternative for use in artificial joints. 相似文献
73.
Nadir Shah Ayaz Ahmad Babar Nazir Depei Qian 《Peer-to-Peer Networking and Applications》2016,9(2):356-371
Due to limited radio range and mobility of nodes in mobile ad hoc networks (MANETs), the network partitioning and merging could occur frequently. When structured peer-to-peer (P2P) overlays are running over MANETs, then network partition in the physical network can also cause network partition at the overlay layer. Existing approaches for structured P2P overlay over MANETs do not detect network partition at the overlay layer. This paper proposes a cross-layer approach to detect network partition at the overlay layer for structured P2P overlay over MANETs. Simulation results show that the proposed approach is highly effective and efficient in terms of routing overhead, success ratio and false-negative ratio. 相似文献
74.
The scarcity of bandwidth in the radio spectrum has become more vital since the demand for more and more wireless applications has increased. Most of the spectrum bands have been allocated although many studies have shown that these bands are significantly underutilized most of the time. The problem of unavailability of spectrum and inefficiency in its utilization has been smartly addressed by the cognitive radio (CR) technology which is an opportunistic network that senses the environment, observes the network changes, and then uses knowledge gained from the prior interaction with the network to make intelligent decisions by dynamically adapting their transmission characteristics. In this paper, some of the decentralized adaptive medium access control (MAC) protocols for CR networks have been critically analyzed, and a novel adaptive MAC protocol for CR networks, decentralized non-global MAC (DNG-MAC), has been proposed. The results show the DNG-MAC outperforms other CR-MAC protocols in terms of time and energy efficiency. 相似文献
75.
Stiction or high static friction is a common problem in spring-diaphragm type control valves, which are widely used in the process industry. Recently, there have been many attempts to understand, define, model and detect stiction in control valves. There are several methods for detecting stiction, but quantification of the actual amount of stiction still remains a challenge. This paper discusses briefly the definition and modelling of stiction. Then it demonstrates a new method to detect and quantify the actual amount of valve stiction using routine operating data. The proposed method is completely data-driven. No additional excitation or experimentation of the plant is required. 相似文献
76.
Notched concrete beams containing varying amounts of pea gravel aggregate were tested under three-point bend, and their fracture toughness determined. The roughness of the region near the interface between the cement paste and the aggregate was evaluated by digitizing images from a confocal tandem scanning microscope. The average roughness of the paste was found to be related to the fracture parametersK
IC (critical stress intensity factor) and a
c (critical crack extension), as determined by the two-parameter fracture model. The roughness in the proximity of the paste-aggregate interface was generally higher than that of the paste far from the aggregate, and it decreased with the distance from the aggregate. This study indicates that aggregate particles increase the toughness of the cement paste portion of concrete, and that this is an important mechanism for toughening concrete. 相似文献
77.
Razzaq Saad Shah Babar Iqbal Farkhund Ilyas Muhammad Maqbool Fahad Rocha Alvaro 《Neural computing & applications》2023,35(11):8017-8026
Neural Computing and Applications - A lot of different methods are being opted for improving the educational standards through monitoring of the classrooms. The developed world uses Smart... 相似文献
78.
The Journal of Supercomputing - Hpcfolder is a user-friendly high-performance computing tool that can be used to analyze the performance of algorithms parallelized using MPI. It is possible to view... 相似文献
79.
Karimulla Shah Rishav Kumar Sibasis Sahoo R. S. Pais Nirupam Chakraborti 《Materials and Manufacturing Processes》2017,32(10):1201-1208
Data-driven models have been constructed for Dual Phase (DP) and Interstitials Free (IF) steels using an evolutionary approach. DP steel data are utilized from an existing database, while for the IF steels, data generated at an integrated steel plant have been used. The objective function for Ultimate Tensile Strength (UTS) and % elongation, created as data-driven models, is simultaneously optimized for an optimum strength-ductility balance and the results indicate the possibilities of developing steels with better mechanical properties than what are known to have been existing so far. 相似文献
80.