全文获取类型
收费全文 | 13538篇 |
免费 | 969篇 |
国内免费 | 110篇 |
专业分类
电工技术 | 205篇 |
综合类 | 61篇 |
化学工业 | 3533篇 |
金属工艺 | 346篇 |
机械仪表 | 489篇 |
建筑科学 | 515篇 |
矿业工程 | 21篇 |
能源动力 | 951篇 |
轻工业 | 1276篇 |
水利工程 | 188篇 |
石油天然气 | 224篇 |
武器工业 | 4篇 |
无线电 | 1378篇 |
一般工业技术 | 2529篇 |
冶金工业 | 490篇 |
原子能技术 | 95篇 |
自动化技术 | 2312篇 |
出版年
2024年 | 70篇 |
2023年 | 268篇 |
2022年 | 587篇 |
2021年 | 891篇 |
2020年 | 751篇 |
2019年 | 812篇 |
2018年 | 911篇 |
2017年 | 827篇 |
2016年 | 807篇 |
2015年 | 474篇 |
2014年 | 748篇 |
2013年 | 1366篇 |
2012年 | 902篇 |
2011年 | 947篇 |
2010年 | 663篇 |
2009年 | 594篇 |
2008年 | 418篇 |
2007年 | 355篇 |
2006年 | 302篇 |
2005年 | 192篇 |
2004年 | 174篇 |
2003年 | 152篇 |
2002年 | 120篇 |
2001年 | 93篇 |
2000年 | 90篇 |
1999年 | 81篇 |
1998年 | 137篇 |
1997年 | 114篇 |
1996年 | 96篇 |
1995年 | 68篇 |
1994年 | 51篇 |
1993年 | 59篇 |
1992年 | 46篇 |
1991年 | 38篇 |
1990年 | 40篇 |
1989年 | 32篇 |
1988年 | 25篇 |
1987年 | 24篇 |
1986年 | 34篇 |
1985年 | 27篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 19篇 |
1980年 | 19篇 |
1979年 | 16篇 |
1978年 | 18篇 |
1977年 | 18篇 |
1976年 | 24篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Eivazzadeh-Keihan Reza Noruzi Ehsan Bahojb Mehrban Sarah Fattahi Aliabadi Hooman Aghamirza Moghim Karimi Meghdad Mohammadi Adibeh Maleki Ali Mahdavi Mohammad Larijani Bagher Shalan Ahmed Esmail 《Journal of Materials Science》2022,57(6):3855-3891
Journal of Materials Science - Chitosan is one of the natural cationic polymers with unique properties such as non-toxicity, biodegradability, biocompatibility, environmentally friendly that has... 相似文献
3.
Hoseinzade Kimia Mousavi-Mashhadi Seyed Ali Shiri Ali 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(12):4648-4658
Journal of Inorganic and Organometallic Polymers and Materials - Immobility of copper on magnetic nanoparticles was performed using surface rectification of Fe3O4 with Agar. The magnetic... 相似文献
4.
Tourajizadeh Hami Yousefzadeh Mahdi Khalaji Ali Keymasi Bamdad Mahdi 《International Journal of Control, Automation and Systems》2022,20(5):1671-1681
International Journal of Control, Automation and Systems - In this paper, a new controllable simulator is proposed and modeled by which, experimental tests of the aircraft’s models can be... 相似文献
5.
Catalysis Letters - In the present paper, an efficient Cu-catalyzed regioselective acylation of indoles with phenylglyoxals was developed which is the first example of indolyl diketones synthesis... 相似文献
6.
Jiao Zhang Junjie Li Ayesha Murtaza Aamir Iqbal Lijuan Zhu Shinawar Waseem Ali Muhammad Usman Roshan Yameen Siyi Pan Wanfeng Hu 《International Journal of Food Science & Technology》2022,57(2):963-973
This work evaluated the synergistic effects of combined high-intensity ultrasound (HIU) with β-cyclodextrin (β-CD) treatments on inhibiting browning of apple juice and explored the mechanism through simulation system. The combined treatment of 300 W HIU with 0.006 g mL−1 β-CD had a synergistic impact on maintaining juice colour, resulting in a 39.06% reduction in browning degree, only a 36.64% decrease in total phenolic content, and a 17.82% reduction in PPO activity. The inhibition of enzymatic browning in simulated system revealed that HIU suppressed the enzyme (Polyphenol oxidase, PPO) and β-CD inhibited enzyme (PPO) and embedded substrate (polyphenol). The results of spectroscopic analysis showed that the particle-size distribution of PPO narrowed, the content of α-helix in the secondary structure increased, the fluorescence intensity increased, and the maximum wavelength was red-shifted after HIU and β-CD treatment. Changes in structure could further result in PPO activity loss. Hence, the combined treatment could synthetically alleviate the browning of apple juice. 相似文献
7.
Seredin P. V. Radam Ali Obaid Goloshchapov D. L. Len’shin A. S. Buylov N. S. Barkov K. A. Nesterov D. N. Mizerov A. M. Timoshnev S. N. Nikitina E. V. Arsentyev I. N. Sharafidinov Sh. Kukushkin S. A. Kasatkin I. A. 《Semiconductors》2022,56(4):253-258
Semiconductors - Abstract—In our work, we carry out a structural-spectroscopic study of AlGaN/GaN epitaxial layers grown by molecular-beam epitaxy with nitrogen-plasma activation on a hybrid... 相似文献
8.
Ahmed Fathy Mohammad Ali Abdelkareem A.G. Olabi Hegazy Rezk 《International Journal of Hydrogen Energy》2021,46(8):6087-6099
Cell temperature and water content of the membrane have a significant effect on the performance of fuel cells. The current-power curve of the fuel cell has a maximum power point (MPP) that is needed to be tracked. This study presents a novel strategy based on a salp swarm algorithm (SSA) for extracting the maximum power of proton-exchange membrane fuel cell (PEMFC). At first, a new formula is derived to estimate the optimal voltage of PEMFC corresponding to MPP. Then the error between the estimated voltage at MPP and the actual terminal voltage of the fuel cell is fed to a proportional-integral-derivative controller (PID). The output of the PID controller tunes the duty cycle of a boost converter to maximize the harvested power from the PEMFC. SSA determines the optimal gains of PID. Sensitivity analysis is performed with the operating fuel cell at different cell temperature and water content of the membrane. The obtained results through the proposed strategy are compared with other programmed approaches of incremental resistance method, Fuzzy-Logic, grey antlion optimizer, wolf optimizer, and mine-blast algorithm. The obtained results demonstrated high reliability and efficiency of the proposed strategy in extracting the maximum power of the PEMFC. 相似文献
9.
Aniruddha Nag Mohammed Asif Ali Jiabei Zhou Makoto Ogawa Tatsuo Kaneko 《大分子材料与工程》2021,306(11):2100459
Aromatic and functional polymers with processibility derived from biobased starting materials are prerequisite considering sustainable society. Poly(2,5-benzimidazole)s are rigid-rod polymers to show ultrahigh thermal stability such as flame retardance, while usually suffer from poor solubility. Here, poly(benzimidazole-co-amide)s are synthesized from two biobased monomers, 3,4-diaminobenzoic acid and a semirigid comonomer, 4-aminohydrocinnamic acid. The copolymers with an amide composition of 80 mol% and higher are soluble in widely used polar solvents to fabricate the films keeping high flame retardance, which is comparable with popular high-performance polymers such as aromatic polyimides, polyetheretherketone, polyphenylene sulfide, etc. 相似文献
10.
Heiba Zein K. Mohamed Mohamed Bakr Farag Noura M. Badawi Ali 《Journal of Materials Science: Materials in Electronics》2022,33(13):10388-10398
Journal of Materials Science: Materials in Electronics - Nano Mn0.95M0.05S (M ≡ Cu, Mg) samples were produced using molten salt solid state reaction method. Rietveld analysis of X-ray... 相似文献