全文获取类型
收费全文 | 41186篇 |
免费 | 3499篇 |
国内免费 | 1636篇 |
专业分类
电工技术 | 2112篇 |
技术理论 | 2篇 |
综合类 | 2489篇 |
化学工业 | 6918篇 |
金属工艺 | 2407篇 |
机械仪表 | 2515篇 |
建筑科学 | 3158篇 |
矿业工程 | 994篇 |
能源动力 | 979篇 |
轻工业 | 2866篇 |
水利工程 | 634篇 |
石油天然气 | 2769篇 |
武器工业 | 227篇 |
无线电 | 5008篇 |
一般工业技术 | 5201篇 |
冶金工业 | 2143篇 |
原子能技术 | 442篇 |
自动化技术 | 5457篇 |
出版年
2024年 | 94篇 |
2023年 | 744篇 |
2022年 | 1051篇 |
2021年 | 1735篇 |
2020年 | 1297篇 |
2019年 | 1085篇 |
2018年 | 1166篇 |
2017年 | 1375篇 |
2016年 | 1270篇 |
2015年 | 1603篇 |
2014年 | 2000篇 |
2013年 | 2553篇 |
2012年 | 2498篇 |
2011年 | 2811篇 |
2010年 | 2467篇 |
2009年 | 2253篇 |
2008年 | 2196篇 |
2007年 | 2167篇 |
2006年 | 2165篇 |
2005年 | 1858篇 |
2004年 | 1266篇 |
2003年 | 1083篇 |
2002年 | 1047篇 |
2001年 | 871篇 |
2000年 | 892篇 |
1999年 | 1084篇 |
1998年 | 947篇 |
1997年 | 823篇 |
1996年 | 819篇 |
1995年 | 631篇 |
1994年 | 541篇 |
1993年 | 377篇 |
1992年 | 341篇 |
1991年 | 254篇 |
1990年 | 192篇 |
1989年 | 166篇 |
1988年 | 135篇 |
1987年 | 105篇 |
1986年 | 75篇 |
1985年 | 56篇 |
1984年 | 56篇 |
1983年 | 26篇 |
1982年 | 36篇 |
1981年 | 25篇 |
1980年 | 20篇 |
1979年 | 12篇 |
1977年 | 7篇 |
1976年 | 7篇 |
1973年 | 5篇 |
1970年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Juan Zhao Jian Zhang Guang Yang Chuanjun Wang Xu Zheng Xiaoxu Tang 《Chemistry and Technology of Fuels and Oils》2021,57(5):847-853
Chemistry and Technology of Fuels and Oils - In this paper, the authors have developed a new device and method for measuring the efficiency of spontaneous imbibition and displacement in a low... 相似文献
52.
53.
Hailong Liang Bo Zhang Dayu Zhou Xintai Guo Yan Li Yanqing Lu Yuanyuan Guo 《Ceramics International》2021,47(9):12137-12143
In this work, we introduced a simple solution processing method to prepare yttrium (Y) doped hafnium oxide (HfO2) based dielectric films. The films had high densities, low surface roughness, maximum permittivity of about 32, leakage current < 1.0 × 10?7 A/cm2 at 2 MV/cm, and breakdown field >5.0 MV/cm. In addition to dielectric performance, we investigated the influence of YO1.5 fraction on the electronic structure between Y doped HfO2 thin films and silicon (Si) substrates. The valence band electronic structure, energy gap and conduction band structure changed linearly with YO1.5 fraction. Given this cost-effective deposition technique and excellent dielectric performance, solution-processed Y doped HfO2 based thin films have the potential for insulator applications. 相似文献
54.
Fen Luo Hexi Tang Xiaoyan Shu Zhi Chen Chen Xu Guilin Wei Dong Wu Shunzhang Chen Haibin Zhang Yi Xie Wenxiao Huang Lan Wang Xirui Lu 《Ceramics International》2021,47(5):6329-6335
To simplify the immobilized process of nuclear waste, synthetic Gd2Zr2O7 ceramic was employed to immobilize simulated An3+ (Nd3+) by spark plasma sintering (SPS) without any ion occupation or valence design. Sintering and characterization of immobilized simulated An3+ with various doping amounts were carried out. The effects of Nd2O3 content on the phase composition, active modes, micro-graph and density of the sintered ceramics were investigated. When the Nd2O3 doped amount reached up to 50 mol%, the raw peak of Nd2O3 existed. The sintered ceramics kept a single fluorite phase when Nd2O3 solubility achieved to 40 mol%. The sintered ceramics presented a well crystalline phase and the elements distributed evenly. In addition, as the Nd2O3 doped amount increase, the density and Vickers hardness values of Nd2O3 doped sample decrease. 相似文献
55.
Hao Liu Jinke Chen Yan Fu Zujin Zhao Ben Zhong Tang 《Advanced functional materials》2021,31(33):2103273
Sensitizing conventional fluorescence (CF) dopants with thermally activated delayed fluorescence (TADF) materials has achieved considerable progress, by which the advantages of TADF materials and CF dopants can be fully harnessed. However, the usually used co-phase configuration of CF dopant-engaged sensitizing systems often encounters exciton loss due to Dexter energy transfer (DET). Herein, an effective out-of-phase configuration is proposed to sensitize CF dopants in the fabrication of white organic light-emitting diodes (WOLEDs). Based on a new efficient sky-blue TADF luminogen DCP-BP-DPAC which has an electroluminescence (EL) peak at 486 nm and an EL efficiency of 26.6%, a green TADF material BDMAC-XT, and a red CF dopant DBP sensitized by BDMAC-XT through an out-of-phase configuration without interlayer, efficient WOLEDs are successfully fabricated. By further adopting orange TBRB or 4CzTPNBu as intermediate sensitizers, more efficient energy transfer to DBP is achieved via Förster energy transfer. Through step-by-step energy transfer and elimination of excess DET process, high-performance all-fluorescent WOLEDs are achieved, providing excellent EL efficiencies over 23.0%, and highly stable white light with a high color rendering index of 87. The outstanding EL performance and high-quality emission color demonstrate the great potential of the proposed out-of-phase design for sensitizing systems of WOLEDs. 相似文献
56.
In this study, chemically bonded phosphate ceramic coatings (CBPCCs) with different contents of aluminum phosphate (AP) are prepared on stainless steel (AISI 304L). Differential scanning calorimetry, X-ray diffraction, contact angle test, and a tribocorrosion experiment are carried out to clarify the role of AP in the tribocorrosion performance of CBPCCs. The results show that, with the increase in the AP content, the enthalpy of curing increases because of the greater formation of the bonding phase AlPO4. Both in static corrosion and in tribocorrosion, the corrosion current density of CBPCCs achieves the lowest value when the weight ratio of AP to polytetrafluoroethylene is about 0.78. Additionally, the influence mechanism of AP on tribocorrosion is clarified. AlPO4 from the reaction between AP and Al2O3 has excellent mechanical properties and can enhance the wear resistance of CBPCCs by reducing the mechanical wear and the increased wear due to corrosion. The alumina particles wrapped by AlPO4 can form a dense and smooth surface and change the direction of electrolyte propagation, which leads to the increase in the tribocorrosion resistance of CBPCCs. 相似文献
58.
Li Qian Chen Yan Sun Shikun Zhu Muyuan Xue Jing Gao Zihan Zhao Jinfeng Tang Yihe 《Water Resources Management》2022,36(12):4799-4817
Water Resources Management - Increasing water consumption in agriculture due to global climate change has posed considerable challenges to food security, thus improving the efficiency of water... 相似文献
59.
Chunsheng Wang Yishuang Wang Mingqiang Chen Defang Liang Zhonglian Yang Wen Cheng Zhiyuan Tang Jun Wang Han Zhang 《International Journal of Hydrogen Energy》2021,46(7):5852-5874
Given the continuing issues of environment and energy, methane dry reforming for syngas production have sparked interest among researchers, but struggled with the process immaturity owing to catalyst deactivation. This review summarizes the recent advances in the development of efficient and stable catalysts with strong resistance to coking and metal sintering, including the application of novel materials, the assessment of advanced characterizations and the compatibility to improved reaction system. One feasible option is the crystalline oxide catalysts (perovskite, pyrochlore, spinel and LDHs), which feature a fine metal dispersion and surface confinement effect via a metal exsolution strategy and exhibit superior reactivity and stability. Some new materials (h-BN, clays and MOFs) also extend the option because of their unique morphology and microstructure. It also is elaborated that progresses were achieved in advanced characterizations application, leading to success in the establishment of reaction mechanisms and attributions to the formed robust catalysts. In addition, the perspective described the upgrade of reaction system to a higher reaction efficiency and milder reaction conditions. The combination of efficient reaction systems and robust catalysts paves a way for a scaling-up application of the process. 相似文献
60.
Chiwu Bu Liu Tao Li Rui Zhao Bo Tang Qingju 《Russian Journal of Nondestructive Testing》2021,57(11):1018-1026
Russian Journal of Nondestructive Testing - Infrared images of aerospace materials were collected by infrared camera and analyzed to evaluate debonding defects. However, it is difficult to identify... 相似文献