全文获取类型
收费全文 | 7819篇 |
免费 | 541篇 |
国内免费 | 22篇 |
专业分类
电工技术 | 103篇 |
综合类 | 7篇 |
化学工业 | 1425篇 |
金属工艺 | 361篇 |
机械仪表 | 508篇 |
建筑科学 | 127篇 |
矿业工程 | 2篇 |
能源动力 | 294篇 |
轻工业 | 659篇 |
水利工程 | 37篇 |
石油天然气 | 10篇 |
无线电 | 1537篇 |
一般工业技术 | 1663篇 |
冶金工业 | 653篇 |
原子能技术 | 88篇 |
自动化技术 | 908篇 |
出版年
2023年 | 92篇 |
2022年 | 63篇 |
2021年 | 223篇 |
2020年 | 187篇 |
2019年 | 180篇 |
2018年 | 282篇 |
2017年 | 259篇 |
2016年 | 281篇 |
2015年 | 228篇 |
2014年 | 367篇 |
2013年 | 526篇 |
2012年 | 498篇 |
2011年 | 591篇 |
2010年 | 414篇 |
2009年 | 478篇 |
2008年 | 411篇 |
2007年 | 359篇 |
2006年 | 332篇 |
2005年 | 256篇 |
2004年 | 241篇 |
2003年 | 226篇 |
2002年 | 178篇 |
2001年 | 192篇 |
2000年 | 131篇 |
1999年 | 113篇 |
1998年 | 266篇 |
1997年 | 182篇 |
1996年 | 132篇 |
1995年 | 100篇 |
1994年 | 100篇 |
1993年 | 82篇 |
1992年 | 54篇 |
1991年 | 49篇 |
1990年 | 38篇 |
1989年 | 42篇 |
1988年 | 31篇 |
1987年 | 25篇 |
1986年 | 25篇 |
1985年 | 11篇 |
1984年 | 23篇 |
1983年 | 18篇 |
1982年 | 13篇 |
1981年 | 10篇 |
1980年 | 13篇 |
1979年 | 7篇 |
1977年 | 9篇 |
1976年 | 14篇 |
1975年 | 4篇 |
1974年 | 4篇 |
1973年 | 5篇 |
排序方式: 共有8382条查询结果,搜索用时 281 毫秒
1.
Aluminum, used as a material for heat exchangers in air conditioners, often has problems of leakage of refrigerant on the Al surface due to corrosion. The problems originate from pitting corrosion of the Al in an external environment. To understand corrosion problems, it is necessary to study the corrosion behavior of Al in various environments. In this study, the effects of environmental factors on the corrosion behavior of Al were studied by the surface analysis and electrochemical testing in 3.5 wt% NaCl solutions, with changes of dissolved oxygen, temperature, and concentration of Cl− and S ions. Among the external environmental factors, the presence of oxygen and the increase of Cl− ion concentration do not significantly affect the corrosion potential of Al, leading to an increase of only 1.1 and 6 times, respectively. There was a significant decrease in the corrosion resistance of Al, approximately 40 and 800 times, respectively, with the increase of concentration of S and temperature. 相似文献
2.
Park Tae-Hwan Lee Hye-Jin Kwon Ryeo-Won Lee In-Ho Lee Seung-Jea Park Jong-In Choo Eon-Ah Lee Jeong-Beom 《Food science and biotechnology》2022,31(9):1207-1212
Food Science and Biotechnology - Caffeine and orexin can affect awakening, neuroendocrine, and sympathetic nerve function. Our previous study has reported that caffeine intake can increase human... 相似文献
3.
Gupta Yubraj Lama Ramesh Kumar Lee Sang-Woong Kwon Goo-Rak 《Multimedia Tools and Applications》2020,79(43-44):32195-32224
Multimedia Tools and Applications - The automatic binary classification of normal and abnormal subjects using magnetic resonance (MR) brain images has made remarkable progress in recent years. This... 相似文献
4.
Wang Hanxiang Li Yanfen Dang L. Minh Ko Jaesung Han Dongil Moon Hyeonjoon 《Multimedia Tools and Applications》2020,79(39-40):29411-29431
Multimedia Tools and Applications - The rapid urbanization process is escalating the urban waste problem, and ineffective management has worsened the issue, leading to severe consequences to the... 相似文献
5.
Sharat Chandra Barman Md. Abu Zahed Md. Sharifuzzaman Seok Gyu Ko Hyosang Yoon Joong San Nah Xing Xuan Jae Yeong Park 《Advanced functional materials》2020,30(14)
Current immunosensors have an insufficient number of binding sites for the recognition of biomolecules, which leads to false positive or negative results. In this research, a facile, cost‐effective, disposable, and highly selective electrochemical immunosensing platform is developed based on cationic polyelectrolyte polyallylamine (PAAMI) anchored laser‐ablated graphene (LAG). Here, for the first time, PAAMI is introduced to stabilize LAG flakes, while retaining the intrinsic thermal and electronic properties of the substrate by noncovalent π–π interaction and electrostatic physical absorption. The sensing platform offers a suitable number of anchoring sites for the immobilized antibodies by providing ? NH2 functional groups. The proper grafting of PAAMI is confirmed through X‐ray photoelectron spectroscopy and Raman spectroscopy. The immunosensing platform is applied to detect immunoglobulin (IgG) biomarkers as a proof of concept. Under optimized conditions, the sensing platform exhibits a linear range of 0.012–15 and 15–352 ng mL?1 with a limit of detection of 6 pg mL?1 for IgG detection with high selectivity. Based on the analysis, the developed immunosensing platform can be used for point‐of‐care detection of IgG in clinical diagnostic centers. Furthermore, the developed strategy is well suited for the detection of other cancer biomarkers after immobilizing the relevant antibodies. 相似文献
6.
7.
Ng Mun-Kit Chong Yung-Wey Ko Kwang-man Park Young-Hoon Leau Yu-Beng 《Neural computing & applications》2020,32(17):13155-13171
Neural Computing and Applications - Warehouse robots have been widely used by manufacturers and online retailer to automate good delivery process. One of the fundamental components when designing a... 相似文献
8.
Hun Soo Jang Seonggwang Yoo Seong Hyeon Kang Jongjun Park Gi‐Gwan Kim Heung Cho Ko 《Advanced functional materials》2020,30(5)
This work demonstrates a means of automatic transformation from planar electronic devices to desirable 3D forms. The method uses a spatially designed thermoplastic framework created via extrusion shear printing of acrylonitrile–butadiene–styrene (ABS) on a stress‐free ABS film, which can be laminated to a membrane‐type electronic device layer. Thermal annealing above the glass transition temperature allows stress relaxation in the printed polymer chains, resulting in an overall shape transformation of the framework. In addition, the significant reduction in the Young's modulus and the ability of the polymer chains to reflow in the rubbery state release the stress concentration in the electronic device layer, which can be positioned outside the neutral mechanical plane. Electrical analyses and mechanical simulations of a membrane‐type Au electrode and indium gallium zinc oxide transistor arrays before and after transformation confirm the versatility of this method for developing 3D electronic devices based on planar forms. 相似文献
9.
Scientometrics - This study describes the increase of research productivity of latecomer countries (latecomers) in the high-energy physics (HEP) community by research strategies based on a national... 相似文献