全文获取类型
收费全文 | 323276篇 |
免费 | 11198篇 |
国内免费 | 5162篇 |
专业分类
电工技术 | 10320篇 |
技术理论 | 1篇 |
综合类 | 6687篇 |
化学工业 | 51196篇 |
金属工艺 | 14606篇 |
机械仪表 | 13244篇 |
建筑科学 | 12270篇 |
矿业工程 | 4259篇 |
能源动力 | 7370篇 |
轻工业 | 30003篇 |
水利工程 | 4262篇 |
石油天然气 | 9426篇 |
武器工业 | 903篇 |
无线电 | 35053篇 |
一般工业技术 | 53846篇 |
冶金工业 | 48796篇 |
原子能技术 | 6932篇 |
自动化技术 | 30462篇 |
出版年
2022年 | 3226篇 |
2021年 | 5455篇 |
2020年 | 4026篇 |
2019年 | 4075篇 |
2018年 | 5781篇 |
2017年 | 6016篇 |
2016年 | 6093篇 |
2015年 | 5932篇 |
2014年 | 8346篇 |
2013年 | 15508篇 |
2012年 | 12249篇 |
2011年 | 14785篇 |
2010年 | 12560篇 |
2009年 | 13200篇 |
2008年 | 13284篇 |
2007年 | 13259篇 |
2006年 | 11964篇 |
2005年 | 10387篇 |
2004年 | 8725篇 |
2003年 | 8027篇 |
2002年 | 7947篇 |
2001年 | 7546篇 |
2000年 | 7068篇 |
1999年 | 6911篇 |
1998年 | 13635篇 |
1997年 | 9848篇 |
1996年 | 7687篇 |
1995年 | 6013篇 |
1994年 | 5296篇 |
1993年 | 5030篇 |
1992年 | 3982篇 |
1991年 | 3636篇 |
1990年 | 3796篇 |
1989年 | 3645篇 |
1988年 | 3437篇 |
1987年 | 2918篇 |
1986年 | 2955篇 |
1985年 | 3360篇 |
1984年 | 3204篇 |
1983年 | 2863篇 |
1982年 | 2713篇 |
1981年 | 2785篇 |
1980年 | 2694篇 |
1979年 | 2600篇 |
1978年 | 2661篇 |
1977年 | 2919篇 |
1976年 | 3783篇 |
1975年 | 2347篇 |
1974年 | 2226篇 |
1973年 | 2352篇 |
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
1.
Feng Wenran Li Zhen Chen Yingying Chen Jinyang Lang Haoze Wan Jianghong Gao Yan Dong Haitao 《Journal of Materials Science》2022,57(3):1881-1889
Journal of Materials Science - Although chalcogenide materials continue to generate considerable interest due to great potentials for various optoelectronic devices, annealing for a long time in... 相似文献
2.
3.
5.
Photoresponsive biomaterials are experiencing a transition from in vitro models to in vivo demonstrations that point toward clinical translation. Dynamic hydrogels for cell encapsulation, light-responsive carriers for controlled drug delivery, and nanomaterials containing photosensitizers for photodynamic therapy are relevant examples. Nonetheless, the step to the clinic largely depends on their combination with technologies to bring light into the body. This review highlights the challenge of photoactivation in vivo, and presents strategies for light management that can be adopted for this purpose. The authors’ focus is on technologies that are materials-driven, particularly upconversion nanoparticles that assist in “direct path” light delivery through tissue, and optical waveguides that “clear the path” between external light source and in vivo target. The authors’ intention is to assist the photoresponsive biomaterials community transition toward medical technologies by presenting light delivery concepts that can be integrated with the photoresponsive targets. The authors also aim to stimulate further innovation in materials-based light delivery platforms by highlighting needs and opportunities for in vivo photoactivation of biomaterials. 相似文献
6.
Julio E. Trevino Swati Mohan Alexandra E. Salinas Emilia Cueva Karen Lozano 《应用聚合物科学杂志》2021,138(28):50665
This study presents the development and characterization of PVDF-conjugated polymer nanofiber-based systems. Five different conducting polymers (CPs) were synthesized successfully and used to create the nanofiber systems. The CPs used are polyaniline (PANI), polypyrrole (PPY), polyindole (PIN), polyanthranilic acid (PANA), and polycarbazole (PCZ). Nanofiber systems were produced utilizing the Forcespinning® technique. The nanofiber systems were developed by mechanical stretching. No electrical field or post-process poling was used in the nanofiber systems. The morphology, structure, electrochemical and piezoelectric performance was characterized. All of the nanofiber PVDF/CP systems displayed higher piezoelectric performance than the fine fiber PVDF systems. The PVDF/PPY nanofiber system displays the highest piezoelectric performance of 15.56 V. The piezoelectric performance of the PVDF/CP nanofiber systems favors potential for an attractive source of energy where highly flexible membranes could be used in power actuators, sensors and portable, and wireless devices to mention some. 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.
Journal of Communications Technology and Electronics - A statistical study of the effectiveness of the non-threshold search procedure for a noise-like phase-shift keyed signal by the delay time is... 相似文献
9.
Tao Feng Mingde Tong Shuotian Yao Hejun Li Shifeng Wen Hongjiao Lin 《Journal of the European Ceramic Society》2021,41(1):158-166
Composites based on hafnium carbide and reinforced with continuous naked carbon fiber with and without PyC interface were prepared at low temperature by precursor infiltration and pyrolysis and chemical vapor deposition method. The microstructure, mechanical property, cyclic ablation and fiber bundle push-in tests of the composites were investigated. The results show that after three times ablation cycles, the bending strength of samples without PyC interface decreased by 63.6 %; the bending strength of samples with PyC interface only decreased by 37.8 %. The force displacement curve of the samples with PyC interface presented a well pseudoplastic deformation state. The mechanical behavior difference of two kinds of composites was due to crucial function of PyC interface phase including protection of fiber and weakening of fiber/matrix interface. 相似文献
10.
Glass and Ceramics - Ceramic bricks based on low-melting clay and ferro-dust from self-disintegrating, low-carbon, ferrochrome slags, graded from M100 to M175, respectively, were obtained in the... 相似文献