全文获取类型
收费全文 | 194471篇 |
免费 | 14294篇 |
国内免费 | 7230篇 |
专业分类
电工技术 | 10210篇 |
技术理论 | 9篇 |
综合类 | 10933篇 |
化学工业 | 32079篇 |
金属工艺 | 11285篇 |
机械仪表 | 11701篇 |
建筑科学 | 11787篇 |
矿业工程 | 4624篇 |
能源动力 | 4353篇 |
轻工业 | 11865篇 |
水利工程 | 3751篇 |
石油天然气 | 11248篇 |
武器工业 | 1258篇 |
无线电 | 20571篇 |
一般工业技术 | 29813篇 |
冶金工业 | 12265篇 |
原子能技术 | 5148篇 |
自动化技术 | 23095篇 |
出版年
2024年 | 789篇 |
2023年 | 2681篇 |
2022年 | 5296篇 |
2021年 | 7186篇 |
2020年 | 5447篇 |
2019年 | 4646篇 |
2018年 | 5824篇 |
2017年 | 6413篇 |
2016年 | 5881篇 |
2015年 | 6741篇 |
2014年 | 8681篇 |
2013年 | 10627篇 |
2012年 | 11471篇 |
2011年 | 12357篇 |
2010年 | 10649篇 |
2009年 | 10373篇 |
2008年 | 10253篇 |
2007年 | 9657篇 |
2006年 | 9032篇 |
2005年 | 7721篇 |
2004年 | 5814篇 |
2003年 | 5476篇 |
2002年 | 5446篇 |
2001年 | 4889篇 |
2000年 | 4320篇 |
1999年 | 3880篇 |
1998年 | 3068篇 |
1997年 | 2593篇 |
1996年 | 2348篇 |
1995年 | 2030篇 |
1994年 | 1693篇 |
1993年 | 1428篇 |
1992年 | 1357篇 |
1991年 | 1187篇 |
1990年 | 1148篇 |
1989年 | 1075篇 |
1988年 | 960篇 |
1987年 | 865篇 |
1986年 | 788篇 |
1985年 | 731篇 |
1984年 | 712篇 |
1982年 | 674篇 |
1979年 | 738篇 |
1978年 | 777篇 |
1977年 | 739篇 |
1976年 | 755篇 |
1975年 | 713篇 |
1974年 | 719篇 |
1973年 | 723篇 |
1972年 | 705篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
Minghuan Wang Xia Chen Wenjun Tong Jiajie Wang Xindi Wang 《The International Journal of Advanced Manufacturing Technology》2020,107(1):157-166
Microdimples as a typical surface texture has been widely used for improving the properties in tribology and heat transfer fields. Ultrasonically assisted 相似文献
152.
153.
Burdin D. A. Savel’ev D. V. Ekonomov N. A. Chashin D. V. Fetisov Yu. K. 《Technical Physics Letters》2020,46(5):487-490
Technical Physics Letters - The magnetoelectric (ME) effect in a planar amorphous ferromagnet–piezoelectric lead zirconate titanate (PZT) composite structure can be effectively excited by... 相似文献
154.
155.
Inam Ridha Ali Basiri Sudhakar Godeshala Md Zubair Ebne Rafique Deepanjan Ghosh Jason Williams Nikhilesh Chawla Jung Keun Lee Jacquelyn Kilbourne Yu Yao Kaushal Rege 《Advanced functional materials》2021,31(6):2007811
Poor strength, infection, leakage, long procedure times, and inflammation limit the efficacy of common tissue sealing devices in surgeries and trauma. Light-activated sealing is attractive for tissue sealing and repair, and can be facilitated by the generation of local heat following absorption of nonionizing laser energy by chromophores. Here, the inherent ability of biomaterials is exploited to absorb nonionizing, mid-infrared (midIR) light in order to engender rapid photothermal sealing and repair of soft tissue wounds. In this approach, the biomaterial simultaneously acts as a photothermal convertor as well as a biosealant, which dispenses the need for exogeneous light-absorbing nanoparticles or dyes. Biomechanical recovery, mathematical modeling, histopathology analyses, tissue strain mapping using digital imaging correlation, and visualization of the biosealant-tissue interface using hyperspectral imaging indicate superior performance of midIR sealing in live mice compared to conventional sutures and glue. The midIR-biosealant approach demonstrates rapid sealing of soft tissues, improves cosmesis, lowers potential for scarring, obviates safety concerns because of the nonionizing light used, and allows adoption of a wide diversity of biomaterials. Taken together, the studies demonstrate a novel advance both in biomaterials for surgical sealing along with the use of nonionizing midIR light, with high potential for clinical translation. 相似文献
156.
Rizwan Ullah Khan Haojie Yu Li Wang Lisong Teng Zain-ul-Abdin Ahsan Nazir Shah Fahad Tarig Elshaarani Fazal Haq Di Shen 《应用聚合物科学杂志》2020,137(46):49424
The development of safe drug carriers is cardinal in cancer therapy, which can target the cancer cells and release the loaded drug on-demand without damaging the healthy cells of the body. In our work, we synthesized three different biodegradable polymers, poly[(ethyl aminobezoate) (ethyl glycinato) phosphazenes] (PABGPs), in different mole ratio of side groups. The successful synthesis of these PABGPs was confirmed by 1H NMR, 31P NMR, FT-IR, and gel permeation chromatography. These PABGPs were fabricated into drug (camptothecin, CPT, a hydrophobic anticancer drug) loaded nanoparticles. These drug-loaded nanoparticles showed good drug release behaviors under normal physiological conditions (pH 7.4 and temperature 37°C). These PABGPs-based nanoparticles may find their application as effective drug carriers for cancer therapy. 相似文献
157.
158.
Siqi Yu Qin Wang Jianwei Wang Yong Xiang Xiaobin Niu Tingshuai Li 《International Journal of Hydrogen Energy》2021,46(27):14331-14337
Artificial nitrogen fixation is emerging as a promising approach for synthesis of ammonia at mild conditions. Inspired by biological nitrogen fixation based on bacteria containing iron, zinc doped Fe2O3 nanoparticles are proposed as an efficient and earth abundant electrocatalyst for converting N2 to NH3. In neutral media, it achieves a maximum Faradaic efficiency (FE) of 10.4% and a large NH3 yield rate of 15.1 μg h?1 mg?1cat. at ?0.5 V vs. reversible hydrogen electrode. This catalyst also exhibits excellent selectivity and stability. Theoretical calculations suggest the reaction follows the associative enzymatic mechanism and it has a barrier of as low as 0.68 eV. 相似文献
159.
Technical Physics Letters - Possible designs of a terahertz laser that use the effect of Bloch oscillations in SiC natural superlattices have been considered. It has been proposed to use as a... 相似文献
160.
The flame front deformation instability of low-velocity filtration combustion within an inert packed bed is studied based on the initial preheating non-uniformity. Based on the experimental phenomena, an initial thermal perturbation model is numerically proposed so as to predict the deformation behaviors of the flame front instabilities. The numerical prediction indicates that the assumption of an initial thermal perturbation is a feasible explanation as the cause of the flame front inclination instability. As the initial thermal perturbation increases, the phenomena of the flame front break and shrinking instabilities could easily occur at high filtration velocity or low equivalence ratio. Moreover, the evolutions of the flame front break rate and the shrinking rate are quantitatively analyzed. 相似文献