全文获取类型
| 收费全文 | 165篇 |
| 免费 | 30篇 |
| 国内免费 | 13篇 |
专业分类
| 电工技术 | 18篇 |
| 综合类 | 22篇 |
| 化学工业 | 23篇 |
| 金属工艺 | 3篇 |
| 机械仪表 | 8篇 |
| 建筑科学 | 5篇 |
| 矿业工程 | 12篇 |
| 能源动力 | 7篇 |
| 轻工业 | 4篇 |
| 水利工程 | 3篇 |
| 石油天然气 | 5篇 |
| 武器工业 | 28篇 |
| 无线电 | 11篇 |
| 一般工业技术 | 17篇 |
| 冶金工业 | 6篇 |
| 原子能技术 | 22篇 |
| 自动化技术 | 14篇 |
出版年
| 2025年 | 2篇 |
| 2024年 | 10篇 |
| 2023年 | 1篇 |
| 2022年 | 11篇 |
| 2021年 | 6篇 |
| 2020年 | 4篇 |
| 2019年 | 9篇 |
| 2018年 | 5篇 |
| 2017年 | 7篇 |
| 2016年 | 4篇 |
| 2015年 | 8篇 |
| 2014年 | 11篇 |
| 2013年 | 13篇 |
| 2012年 | 13篇 |
| 2011年 | 10篇 |
| 2010年 | 13篇 |
| 2009年 | 5篇 |
| 2008年 | 8篇 |
| 2007年 | 14篇 |
| 2006年 | 11篇 |
| 2005年 | 6篇 |
| 2004年 | 6篇 |
| 2003年 | 3篇 |
| 2002年 | 7篇 |
| 2001年 | 4篇 |
| 2000年 | 5篇 |
| 1999年 | 3篇 |
| 1998年 | 2篇 |
| 1997年 | 1篇 |
| 1996年 | 2篇 |
| 1995年 | 1篇 |
| 1994年 | 1篇 |
| 1993年 | 1篇 |
| 1991年 | 1篇 |
排序方式： 共有208条查询结果，搜索用时 15 毫秒
61.
采用滑动弧等离子体制备出不同颗粒形貌和锐钛矿相初始含量(fA)的纳米TiO2粉体。采用X射线衍射(XRD)、透射电镜(TEM)和物理吸附仪对焙烧前后的样品进行表征, 考察了焙烧温度对纳米TiO2的晶相组成、晶体粒径、比表面积(SBET)和颗粒形貌的影响。通过光催化氧化亚甲基蓝反应评价样品焙烧后的光催化活性。结果表明, 滑动弧等离子体制备的纳米TiO2的锐钛矿相向金红石相转变温度约为650℃, 锐钛矿相向金红石相的转变速率取决于焙烧温度、颗粒形貌和锐钛矿相初始含量。随焙烧温度升高, 球形颗粒的锐钛矿晶体粒径略微增大, SBET缓慢减小; 非球形颗粒的锐钛矿晶体粒径快速增大, SBET迅速减小。随着fA的增加, 纳米TiO2粉体的光催化表观反应速率常数(k)呈现三种不同的变化趋势: 当fA<70%时, k随之缓慢增加; 当70%<fA<85%时, k随之快速增加; 当fA>85%时, k转为快速降低。 相似文献
62.
Phugoid dynamic characteristic of hypersonic gliding vehicles 总被引：2，自引：0，他引：2
CHEN XiaoQing HOU ZhongXi LIU JianXia & CHEN XiaoQian College of Aerospace Materials Engineering National University of Defense Technology Changsha China 《中国科学:信息科学(英文版)》2011,(3):542-550
This paper focuses on the phugoid dynamic characteristic of hypersonic gliding vehicle. By regarding equilibrium glide as the fixed state of reentry trajectory, the dynamic equations are simplified and a hyper-geometric equation with a forcing function is deduced. Linearization theory is applied to analyze the characteristic of the motion, and the phugoid mode is found to be stable. An analytical solution of flight path angle as a function of speed is derived based on General Multiple Scale theory. The dyna... 相似文献
63.
偏航控制过程中,滑动式偏航系统载荷特性是影响风力发电偏航系统安全可靠性的关键因素,现以2 MW风力发电机为研究对象,采用IEC标准中Von Kamman谱模拟湍流风,考虑重力载荷、气动载荷及惯性载荷的影响,建立风力发电机组模型,基于Bladed软件仿真风力发电机偏航时机组的动态特性,研究偏航时风况、偏航速度及偏航角度对滑动式偏航系统荷载的影响规律,为风力发电机的运行维护及改进设计提供依据。研究结果表明,偏航过程中同时变桨,变桨速率对偏航轴承的荷载有重要影响。湍流强度影响偏航轴承的疲劳和极端载荷的波动情况,偏航速度越大,偏航轴承处极限荷载越大。 相似文献
64.
The gliding arc can offer high energy efficiency and selectivity for chemical reactions and has been widely applied in material processing, environmental protection and other industrial areas. But the discharge properties, measurement of plasma parameters and related physical pro- cesses of the gliding arc discharge still need to further studied. In this study, the gliding arc was driven by the transverse magnetic field to produce the non-equilibrium plasma at high pressure. The parameters of the plasma at our observed point were measured by optical methods. The experimental result shows that the electron temperature is about 0.6 eV and the heavy particle temperature is approximately 2987±250 K. 相似文献
65.
编织袋扁丝纱锭绕制机往复螺杆的设计与改进 总被引：1，自引：0，他引：1
为了解决绕丝机绕成扁丝纱锭合格率低的问题,分析发现其原因是绕丝头关键零件——往复螺杆的质量难以保证,提出将传统的以45结构钢制造整体往复螺杆的工艺,改为将其滑线部分做成以尼龙1010为基体,中心轴仍为45结构钢的加工工艺,克服了原用材料加工难,精度难保证问题,同时,提出结合调整绕丝张力也可以达到提高纱锭卷绕紧度的要求。 相似文献
66.
Aline da Graa Sampaio William Chiappim Noala Vicensoto Moreira Milhan Benedito Botan Neto Rodrigo Pessoa Cristiane Yumi Koga-Ito 《International journal of molecular sciences》2022,23(22)
In this study, different plasma-activated liquids were evaluated for their antimicrobial effects against Escherichia coli, as well as for their cytotoxicity on mammalian cells. The PALs were prepared from distilled (DIS), deionized (DI), filtered (FIL), and tap (TAP) water. Additionally, 0.9% NaCl saline solution (SAL) was plasma-activated. These PALs were prepared using 5 L/min air gliding arc plasma jet for up to 60.0 min of exposure. Subsequently, the physicochemical properties, such as, the oxidation-reduction potential (ORP), the pH, the conductivity, and the total dissolved solids (TDS) were characterized by a water multiparameter. The PALs obtained showed a drastic decrease in the pH with increasing plasma exposure time, in contrast, the conductivity and TDS increased. In a general trend, the UV-vis analyses identified a higher production of the following reactive species of nitrogen and oxygen (RONS), HNO2, H2O2, NO3−, and NO2−. Except for the plasma-activated filtered water (PAW-FIL), where there was a change in the position of NO2− and NO3− at some pHs, The higher production of HNO2 and H2O2-reactive species was observed at a low pH. Finally, the standardized suspensions of Escherichia coli were exposed to PAL for up to 60.0 min. The plasma-activated deionized water (PAW-DI pH 2.5), plasma-activated distilled water (PAW-DIS pH 2.5 and 3), and plasma-activated tap water (PAW-TAP 3.5) showed the best antimicrobial effects at exposure times of 3.0, 10.0, and 30.0 min, respectively. The MTT analysis demonstrated low toxicity of all of the PAL samples. Our results indicate that the plasma activation of different liquids using the gliding arc system can generate specific physicochemical conditions that produce excellent antibacterial effects for E. coli with a safe application, thus bringing future contributions to creating new antimicrobial protocols. 相似文献
67.
Filamentous cyanobacteria, forming long strands of connected cells, are one of the earliest and most successful forms of life on Earth. They exhibit self-organized behaviour, forming large-scale patterns in structures like biomats and stromatolites. The mechanical properties of these rigid structures have contributed to their biological success and are important to applications like algae-based biofuel production. For active polymers like these cyanobacteria, one of the most important mechanical properties is the bending modulus, or flexural rigidity. Here, we quantify the bending stiffness of three species of filamentous cyanobacteria, of order Oscillatoriales, using a microfluidic flow device where single filaments are deflected by fluid flow. This is complemented by measurements of Young’s modulus of the cell wall, via nanoindentation, and the cell wall thickness. We find that the stiffness of the cyanobacteria is well-captured by a simple model of a flexible rod, with most stress carried by a rigid outer wall. Finally, we connect these results to the curved shapes that these cyanobacteria naturally take while gliding, and quantify the forces generated internally to maintain this shape. The measurements can be used to model interactions between cyanobacteria, or with their environment, and how their collective behaviour emerges from such interactions. 相似文献
68.
黔西南晴隆大厂锑矿田构造控矿特征 总被引：1，自引：0，他引：1
大厂锑矿田是我国西南地区著名的大型锑矿产地之一.矿田中矿床受构造控制明显.区域性近东西向基底构造控制了矿田的展布;北东向主干构造控制了矿床的分布;北东向主干断裂派生的北北东向和北东东向断裂、层间断裂及其派生构造共同控制了矿体和矿脉的分布. 相似文献
69.
湖南涟源凹陷西部滑脱带构造特征 总被引：6，自引：0，他引：6
涟源凹陷西部逆冲推覆构造和重力滑动构造并存，前者表现为逆冲叠瓦扇，其主干断层向下收敛于加里东不整合面附近，总体沿加里东不整合面向西逆冲推覆，后者则表现为滑片型和滑福型两类，总体向东滑动。上述滑脱构造对煤层结构和煤厚变化具有明显的影响，它使煤层原生结构破坏形成各种构造煤，并导致煤层厚度重新分配，形成ＮＥ－ＮＮＥ向展布的厚薄煤带。 相似文献
70.
以简化模型做理论分析，以Mohr-Coulomb平衡理论作分析工具，分析了在基坑开挖时软土地基滑鼓破坏机制和抗滑系数与基桩插入深度及地基土内摩擦角的关系，对支护方案提供了应对策略。 相似文献