全文获取类型
收费全文 | 26469篇 |
免费 | 1716篇 |
国内免费 | 65篇 |
专业分类
电工技术 | 378篇 |
综合类 | 32篇 |
化学工业 | 6069篇 |
金属工艺 | 1015篇 |
机械仪表 | 1550篇 |
建筑科学 | 514篇 |
矿业工程 | 9篇 |
能源动力 | 1057篇 |
轻工业 | 2185篇 |
水利工程 | 114篇 |
石油天然气 | 43篇 |
武器工业 | 2篇 |
无线电 | 4408篇 |
一般工业技术 | 5762篇 |
冶金工业 | 1963篇 |
原子能技术 | 381篇 |
自动化技术 | 2768篇 |
出版年
2024年 | 26篇 |
2023年 | 305篇 |
2022年 | 459篇 |
2021年 | 760篇 |
2020年 | 577篇 |
2019年 | 650篇 |
2018年 | 848篇 |
2017年 | 838篇 |
2016年 | 964篇 |
2015年 | 755篇 |
2014年 | 1187篇 |
2013年 | 1703篇 |
2012年 | 1757篇 |
2011年 | 2165篇 |
2010年 | 1579篇 |
2009年 | 1631篇 |
2008年 | 1506篇 |
2007年 | 1163篇 |
2006年 | 996篇 |
2005年 | 860篇 |
2004年 | 780篇 |
2003年 | 722篇 |
2002年 | 699篇 |
2001年 | 600篇 |
2000年 | 537篇 |
1999年 | 533篇 |
1998年 | 833篇 |
1997年 | 526篇 |
1996年 | 480篇 |
1995年 | 318篇 |
1994年 | 195篇 |
1993年 | 190篇 |
1992年 | 137篇 |
1991年 | 128篇 |
1990年 | 104篇 |
1989年 | 101篇 |
1988年 | 89篇 |
1987年 | 73篇 |
1986年 | 57篇 |
1985年 | 52篇 |
1984年 | 41篇 |
1983年 | 35篇 |
1982年 | 37篇 |
1981年 | 33篇 |
1980年 | 35篇 |
1979年 | 17篇 |
1977年 | 30篇 |
1976年 | 43篇 |
1975年 | 21篇 |
1974年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Hong Sae Jin Park Nam Il Hwang Dae Keun Yi Tae Gyu Eum Hyang Lan 《Food science and biotechnology》2022,31(6):669-679
Food Science and Biotechnology - Various hilling materials (rice hulls, pine sawdust, and perlite) were compared to produce sprout vegetables using beach silvertop (Glehnia littoralis Fr. Schm. ex... 相似文献
2.
International Journal of Information Security - Machine learning techniques have been widely used and shown remarkable performance in various fields. Along with the widespread utilization of... 相似文献
3.
4.
Hyun Sun Choi Yun Kee Jo Gwang-Noh Ahn Kye Il Joo Dong-Pyo Kim Hyung Joon Cha 《Advanced functional materials》2021,31(46):2104602
The esophagus is a tubular-shaped muscular organ where swallowed fluids and muscular contractions constitute a highly dynamic environment. The turbulent, coordinated processes that occur through the oropharyngeal conduit can often compromise targeted administration of therapeutic drugs to a lesion, significantly reducing therapeutic efficacy. Here, magnetically guidable drug vehicles capable of strongly adhering to target sites using a bioengineered mussel adhesive protein (MAP) to achieve localized delivery of therapeutic drugs against the hydrodynamic physiological conditions are proposed. A suite of highly uniform microparticles embedded with iron oxide (IO) nanoparticles (MAP@IO MPs) is microfluidically fabricated using the genipin-mediated covalent cross-linking of bioengineered MAP. The MAP@IO MPs are successfully targeted to a specific region and prolongedly retained in the tubular-structured passageway. In particular, orally administered MAP@IO MPs are effectively captured in the esophagus in vivo in a magnetically guidable manner. Moreover, doxorubicin (DOX)-loaded MAP@IO MPs exhibit a sustainable DOX release profile, effective anticancer therapeutic activity, and excellent biocompatibility. Thus, the magnetically guidable locomotion and robust underwater adhesive properties of the proteinaceous soft microbots can provide an intelligent modular approach for targeted locoregional therapeutics delivery to a specific lesion site in dynamic fluid-associated tubular organs such as the esophagus. 相似文献
5.
6.
Food Science and Biotechnology - Aluminum based reflective nanolens arrays were developed via a series of aluminum electropolishing and anodization steps with subsequent selective dissolution of... 相似文献
7.
8.
Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than... 相似文献
9.
Eui Dae Jung Amit Kumar Harit Do Hui Kim Chung Hyeon Jang Jong Hyun Park Shinuk Cho Myoung Hoon Song Han Young Woo 《Advanced materials (Deerfield Beach, Fla.)》2020,32(30):2002333
A series of anionic conjugated polyelectrolytes (CPEs) is synthesized based on poly(fluorene-co-phenylene) by varying the side-chain ionic density from two to six per repeat units (MPS2-TMA, MPS4-TMA, and MPS6-TMA). The effect of MPS2, 4, 6-TMA as interlayers on top of a hole-extraction layer of poly(bis(4-phenyl)-2,4,6-trimethylphenylamine (PTAA) is investigated in inverted perovskite solar cells (PeSCs). Owing to the improved wettability of perovskites on hydrophobic PTAA with the CPEs, the PeSCs with CPE interlayers demonstrate a significantly enhanced device performance, with negligible device-to-device dependence relative to the reference PeSC without CPEs. By increasing the ionic density in the MPS-TMA interlayers, the wetting, interfacial defect passivation, and crystal growth of the perovskites are significantly improved without increasing the series resistance of the PeSCs. In particular, the open-circuit voltage increases from 1.06 V for the PeSC with MPS2-TMA to 1.11 V for the PeSC with MPS6-TMA. The trap densities of the PeSCs with MPS2,4,6-TMA are further analyzed using frequency-dependent capacitance measurements. Finally, a large-area (1 cm2) PeSC is successfully fabricated with MPS6-TMA, showing a power conversion efficiency of 18.38% with negligible hysteresis and a stable power output under light soaking for 60 s. 相似文献