全文获取类型
收费全文 | 9458篇 |
免费 | 1108篇 |
国内免费 | 449篇 |
专业分类
电工技术 | 152篇 |
技术理论 | 2篇 |
综合类 | 535篇 |
化学工业 | 4597篇 |
金属工艺 | 567篇 |
机械仪表 | 249篇 |
建筑科学 | 342篇 |
矿业工程 | 174篇 |
能源动力 | 206篇 |
轻工业 | 560篇 |
水利工程 | 54篇 |
石油天然气 | 360篇 |
武器工业 | 51篇 |
无线电 | 634篇 |
一般工业技术 | 2101篇 |
冶金工业 | 280篇 |
原子能技术 | 59篇 |
自动化技术 | 92篇 |
出版年
2024年 | 29篇 |
2023年 | 155篇 |
2022年 | 246篇 |
2021年 | 328篇 |
2020年 | 332篇 |
2019年 | 298篇 |
2018年 | 344篇 |
2017年 | 416篇 |
2016年 | 387篇 |
2015年 | 397篇 |
2014年 | 573篇 |
2013年 | 591篇 |
2012年 | 713篇 |
2011年 | 690篇 |
2010年 | 495篇 |
2009年 | 546篇 |
2008年 | 477篇 |
2007年 | 573篇 |
2006年 | 553篇 |
2005年 | 541篇 |
2004年 | 452篇 |
2003年 | 415篇 |
2002年 | 372篇 |
2001年 | 255篇 |
2000年 | 174篇 |
1999年 | 130篇 |
1998年 | 97篇 |
1997年 | 68篇 |
1996年 | 62篇 |
1995年 | 48篇 |
1994年 | 39篇 |
1993年 | 26篇 |
1992年 | 40篇 |
1991年 | 38篇 |
1990年 | 43篇 |
1989年 | 30篇 |
1988年 | 3篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1980年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1959年 | 2篇 |
1951年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Pengcheng Xu Shuanbao Guo Haitao Yu Xinxin Li 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(12):2404-2412
The study reports the effect of mesoporous silica nanoparticles (MSNs) on detoxification of toxic organophorous compounds. Based on gravimetric sensing experiment with resonant microcantilever, rapid adsorption of the organophorous simulant of dimethyl methylphosphonate (DMMP) onto MSNs is confirmed. The experimentally observed irreversible gravimetric‐signal implies that substitution‐reaction possibly occurs at the nanomaterial surface. By exploring a method of gravimetric detection at different temperatures to obtain two isotherms, high reaction‐heat of 97.1 kJ mol?1 is extracted that indicates strong chemical interaction. Characterizations with solid‐state NMR and FT‐IR to the MSNs are performed during the adsorption/interaction process, revealing that substitution‐reaction exactly occurs. GC‐MS analysis to the post‐reaction vapor exhaust indicates that one or two methyl groups in a DMMP molecule can be substituted by hydrogen atom(s) through substitution‐reaction with silanol group(s) of MSNs, thereby, destructing DMMP into two sorts of new molecules. With such comprehensive analyses, the destruction/detoxification mechanism is clearly identified. To evaluate the detoxification performance of the MSNs, real toxic of dichlorvos is experimentally examined, resulting in that organophosphate dichlorvos is detoxified into non‐toxic dimethylphosphate. The low‐cost and producible MSNs are promising for detoxification to organophorous compounds. Besides, the micro‐gravimetric analysis method can be expanding for extensive researches on various functional materials. 相似文献
992.
993.
Jonas Croissant Arnaud Chaix Olivier Mongin Miao Wang Sébastien Clément Laurence Raehm Jean‐Olivier Durand Vincent Hugues Mireille Blanchard‐Desce Marie Maynadier Audrey Gallud Magali Gary‐Bobo Marcel Garcia Jie Lu Fuyuhiko Tamanoi Daniel P. Ferris Derrick Tarn Jeffrey I. Zink 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(9):1752-1755
994.
995.
Jun Zhang Surajit Karmakar Meihua Yu Neena Mitter Jin Zou Chengzhong Yu 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(24):5068-5076
A rationally designed two‐step synthesis of silica vesicles is developed with the formation of vesicular structure in the first step and fine control over the entrance size by tuning the temperature in the second step. The silica vesicles have a uniform size of ≈50 nm with excellent cellular uptake performance. When the entrance size is equal to the wall thickness, silica vesicles after hydrophobic modification show the highest loading amount (563 mg/g) towards Ribonuclease A with a sustained release behavior. Consequently, the silica vesicles are excellent nano‐carriers for cellular delivery applications of therapeutical biomolecules. 相似文献
996.
为实现微纳尺度器件三维几何形貌测量及表征,基于电容和压阻原理,开发了两种三维微接触式测头。其中电容测头测量范围4.5μm,轴向分辨力和横向分辨力分别为10 nm和25 nm;压阻测头测量范围4.6μm,轴向分辨力和横向分辨力分别为5 nm和10 nm。两种测头均可集成到纳米测量机,实现微结构几何参数的测量。 相似文献
997.
Georgy Terentyuk Elizaveta Panfilova Vitaly Khanadeev Daniil Chumakov Elina Genina Alexey Bashkatov Valery Tuchin Alla Bucharskaya Galina Maslyakova Nikolai Khlebtsov Boris Khlebtsov 《Nano Research》2014,7(3):325-337
Nanocomposites (NCs) consisting of a gold nanorod core and a mesoporous silica shell doped with hematoporphyrin (HP) have been fabricated in order to improve the efficiency of cancer treatment by combining photothermal and photodynamic therapies (PDT + PTT) in vivo. In addition to the long-wavelength plasmon resonance near 810-830 nm, the fabricated NCs exhibited a 400-nm absorbance peak corresponding to bound HP, generated singlet oxygen under 633-nm excitation near the 632.5-nm Q-band, and produced heat under a 808-nm near-infrared (NIR) laser irradiation. These modalities were used for a combined PDT + PTT treatment of large (about 3 cm3) solid tumors in vivo with a xenorafted tumor rat model. NCs were directly injected into tumors and irradiated simultaneously with 633-nm and 808-nm lasers to stimulate the combined photodynamic and photothermal activities of NCs. The efficiency of the combined therapy was evaluated by optical coherence tomography, histological analysis, and by measurements of the tumor volume growth during a 21-day period. The NC-mediated PDT led to weak changes in tissue histology and to a moderate 20% decrease in the tumor volume. In contrast, the combined PDT + PTT treatment resulted in the large-area tumor necrosis and led to dramatic decrease in the tumor volume. 相似文献
998.
Xin He Jun Wang Richard Kloepsch Steffen Krueger Haiping Jia Haidong Liu Britta Vortmann Jie Li 《Nano Research》2014,7(1):110-118
A high voltage layered Li1.2Ni0.16Co0.08Mn0.56O2 cathode material with a hollow spherical structure has been synthesized by molten-salt method in a NaCI flux. Characterization by X-ray diffraction and scanning electron microscopy confirmed its structure and proved that the as-prepared powder is constituted of small, homogenously sized hollow spheres (1-1.5 μm). The material exhibited enhanced rate capability and high first cycle efficiency due to the good dispersion of secondary particles. Galvanostatic cycling at different temperatures (20, 40, and 60 ℃) and a current rate of 2 C (500 mA.g-1) showed no significant capacity fade. 相似文献
999.
A highly pure, small particle-sized and high surface area nano silica powder was prepared from rice husk using alkali extraction, followed by an acid precipitation method. The composition, phase, morphology, size and surface area of the as-synthesised nano silica powder was investigated by energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, transmission electron microscopy, particle size analyser and BET surface area analyser. High-purity nano silica powder was obtained by sodium hydroxide (NaOH) purification treatment (0.5, 1, 1.5, 2 and 2.5?N). The high purity of silica (~99.9%) was obtained at 2.5?N NaOH treatment. The pure nano silica powder that is obtained shows an average particle size of ~25?nm with a high-specific surface area (SSA) of 274?m2?g?1, with an average pore diameter of 1.46?nm. 相似文献
1000.