全文获取类型
收费全文 | 55778篇 |
免费 | 5259篇 |
国内免费 | 2707篇 |
专业分类
电工技术 | 3635篇 |
技术理论 | 6篇 |
综合类 | 3977篇 |
化学工业 | 9131篇 |
金属工艺 | 2831篇 |
机械仪表 | 3374篇 |
建筑科学 | 4417篇 |
矿业工程 | 1537篇 |
能源动力 | 1812篇 |
轻工业 | 4102篇 |
水利工程 | 1083篇 |
石油天然气 | 2437篇 |
武器工业 | 542篇 |
无线电 | 6584篇 |
一般工业技术 | 6596篇 |
冶金工业 | 3436篇 |
原子能技术 | 737篇 |
自动化技术 | 7507篇 |
出版年
2024年 | 184篇 |
2023年 | 976篇 |
2022年 | 1683篇 |
2021年 | 2491篇 |
2020年 | 1820篇 |
2019年 | 1538篇 |
2018年 | 1685篇 |
2017年 | 1828篇 |
2016年 | 1657篇 |
2015年 | 2266篇 |
2014年 | 2807篇 |
2013年 | 3378篇 |
2012年 | 3737篇 |
2011年 | 3826篇 |
2010年 | 3605篇 |
2009年 | 3454篇 |
2008年 | 3332篇 |
2007年 | 2924篇 |
2006年 | 2915篇 |
2005年 | 2313篇 |
2004年 | 1697篇 |
2003年 | 1434篇 |
2002年 | 1521篇 |
2001年 | 1376篇 |
2000年 | 1199篇 |
1999年 | 1258篇 |
1998年 | 1386篇 |
1997年 | 1049篇 |
1996年 | 912篇 |
1995年 | 636篇 |
1994年 | 592篇 |
1993年 | 424篇 |
1992年 | 339篇 |
1991年 | 247篇 |
1990年 | 197篇 |
1989年 | 180篇 |
1988年 | 133篇 |
1987年 | 104篇 |
1986年 | 85篇 |
1985年 | 74篇 |
1984年 | 56篇 |
1983年 | 52篇 |
1982年 | 58篇 |
1981年 | 56篇 |
1980年 | 40篇 |
1979年 | 34篇 |
1978年 | 19篇 |
1977年 | 27篇 |
1976年 | 55篇 |
1973年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 24 毫秒
31.
Mizuki Tenjimbayashi Sadaki Samitsu Yuko Watanabe Yasuyuki Nakamura Masanobu Naito 《Advanced functional materials》2021,31(21):2010957
Liquid marble (LM) is a droplet that is wrapped by hydrophobic solid particles, which behave as a non-wetting soft solid. Based on these properties, LM can be applied in fluidics and soft device applications. A wide variety of functional particles have been synthesized to form functional LMs. However, the formation of multifunctional LMs by integrating several types of functional particles is challenging. Here, a general strategy for the flexible patterning of functional particles on droplet surfaces in a patchwork-like design is reported. It is shown that LMs can switch their macroscopic behavior between a stable and active state on super-repellent surfaces in situ by jamming/unjamming the surface particles. Active LMs hydrostatically coalesce to form a self-sorted particle pattern on the droplet surface. With the support of LM handling robotics, on-demand cyclic activation–manipulation–coalescence–stabilization protocols by LMs with different sizes and particle types result in the reliable design of multi-faced LMs. Based on this concept, a single bi-functional LM is designed from two mono-functional LMs as an advanced droplet carrier. 相似文献
32.
Xiao-Ya Shangguan Bao-Lun Fang Chen-Xiao Xu Yuan Tan Yan-Gang Chen Zhi-Jun Xia Wei Chen 《Ceramics International》2021,47(5):6318-6328
A series of direct Z-scheme FeIn2S4/Bi2WO6 hierarchical heterostructures with intimate interface contacts were synthesized by in-situ growth route and characterized by systematical analyses. All as-prepared FeIn2S4/Bi2WO6 nanocomposites showed significantly enhanced photocatalytic activity towards photodegradation for the removal of tetracycline hydrochloride (TCH) in comparison with individual FeIn2S4 and Bi2WO6. Meanwhile, the highest photocatalytic degradation activity can be achieved by modulating adding amount of FeIn2S4 in FeIn2S4/Bi2WO6 nanocomposites and the optimized component ratio of FeIn2S4 to Bi2WO6 is determined to be 10 wt%. The enhanced photocatalytic activity could be ascribed to efficient separation between photogenerated holes and electrons based on the construction of direct Z-scheme system. The high photocatalytic stability of resultant 10 wt% FeIn2S4/Bi2WO6 nanocomposites was revealed through six successive recycling reactions. The main intermediate generated during TCH photodegradation was explored by HPLC-MS. Besides, the direct Z-scheme photocatalytic mechanism was confirmed by band position analysis, electron spin resonance (ESR) and active species capture experiment. 相似文献
33.
34.
采用正硅酸乙酯(TEOS)和3-氨丙基三乙氧基硅烷(APTES)通过共缩聚法合成介孔二氧化硅(MCM-41)。首先对其氨基修饰,再通过有机合成接枝—R基团(—R:—CHO、—OH、—CH3、—COOH),制备得到Me-Ph-NH-MCM-41、OHC-Ph-NH-MCM-41、HO-Ph-NH-MCM-41、HOOC-Ph-NH-MCM-41四种不同的药物载体。利用FT-IR、Zeta电位、XRD和SEM对其结构和形貌表征,结果表明NH2-MCM-41改性成功。以罗丹明B(RhB)为模型进行载药性能测试,并考察了此释药系统在模拟不同pH的体液下的敏感释药行为,同时探究了不同—R基团对释药的影响。结果显示,四种载体在中性条件下几乎不发生药物释放,通过改变环境体系pH可以有效控制药物释放,其释药行为可以用Korsmeyer-Peppas动力学模型来描述。实验表明,释药量:RhB@HOOC-Ph-NH-MCM-41>RhB@OHC-Ph-NH-MCM-41>RhB@HO-Ph-NH-MCM-41>RhB@Me-Ph-NH-MCM-41,不同—R基团的药物载体的pH响应性不同,其中RhB@HOOC-Ph-NH-MCM-41释药量在pH=1.2时可达57.87%,在用于药物智能控释材料方面具有一定的应用潜力。 相似文献
35.
Debin Wang Jingsong Liu Mengshi Zeng Chunmei Zhang Huiqin Li Hongtao Yu Ying Yuan Shuren Zhang 《Journal of the American Ceramic Society》2019,102(7):4029-4037
(1-x)Sr0.7Pb0.15Bi0.1TiO3-xBi4Ti3O12 ((1-x)SPBT-xBIT, x = 0-0.125) bulk ceramics were developed and calcined via the solid-state method, aimed at the application of pulsed power capacitors. The phase structures, temperature stability, hysteresis loop, and discharge properties were systematically investigated. Considering both the temperature stability and dielectric properties, 0.925SPBT-0.075BIT bulk ceramics with a capacitance variation satisfying the X7R specification were developed for pulsed power capacitors. The energy storage density was 0.252 J/cm3, and the ceramics showed high temperature stability at 80 kV/cm. The discharge current waveforms of the 0.925SPBT-0.075BIT ceramics were recorded. A high discharge power density of approximately 1.01 × 108 W/kg with an 8 Ω load resistor and short discharge period of 84 ns were achieved at 50 kV/cm. The good temperature stability properties and high power density show that the 0.925SPBT-0.075BIT ceramics are well suited for pulsed power capacitors with a wide temperature range. 相似文献
36.
Multifunctional 3D Patternable Drug‐Embedded Nanocarrier‐Based Interfaces to Enhance Signal Recording and Reduce Neuron Degeneration in Neural Implantation 下载免费PDF全文
37.
38.
Multimedia Tools and Applications - In Wyner-Ziv (WZ) video coding, decoder side information (SI) takes a key role in a WZ video codec among other building blocks. In this paper, we review the... 相似文献
39.
40.
To improve the electrochemical properties of rare-earth–Mg–Ni-based hydrogen storage alloys, the effects of stoichiometry and Cu-substitution on the phase structure and thermodynamic properties of the ... 相似文献