全文获取类型
收费全文 | 12840篇 |
免费 | 1701篇 |
国内免费 | 803篇 |
专业分类
电工技术 | 5184篇 |
综合类 | 765篇 |
化学工业 | 1433篇 |
金属工艺 | 1180篇 |
机械仪表 | 613篇 |
建筑科学 | 286篇 |
矿业工程 | 182篇 |
能源动力 | 678篇 |
轻工业 | 139篇 |
水利工程 | 104篇 |
石油天然气 | 510篇 |
武器工业 | 94篇 |
无线电 | 1754篇 |
一般工业技术 | 1055篇 |
冶金工业 | 270篇 |
原子能技术 | 108篇 |
自动化技术 | 989篇 |
出版年
2024年 | 64篇 |
2023年 | 208篇 |
2022年 | 323篇 |
2021年 | 372篇 |
2020年 | 479篇 |
2019年 | 399篇 |
2018年 | 376篇 |
2017年 | 496篇 |
2016年 | 502篇 |
2015年 | 537篇 |
2014年 | 709篇 |
2013年 | 661篇 |
2012年 | 927篇 |
2011年 | 1145篇 |
2010年 | 835篇 |
2009年 | 845篇 |
2008年 | 801篇 |
2007年 | 964篇 |
2006年 | 843篇 |
2005年 | 632篇 |
2004年 | 601篇 |
2003年 | 462篇 |
2002年 | 410篇 |
2001年 | 328篇 |
2000年 | 309篇 |
1999年 | 249篇 |
1998年 | 182篇 |
1997年 | 148篇 |
1996年 | 113篇 |
1995年 | 109篇 |
1994年 | 73篇 |
1993年 | 62篇 |
1992年 | 57篇 |
1991年 | 43篇 |
1990年 | 21篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 11篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1980年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Ibuprofen is a well-known nonsteroidal anti-inflammatory drug, which can interact with lipid membranes. In this paper, the interaction of ibuprofen with bilayer lipid membrane was studied by UV-vis spectroscopy, cyclic voltammetry and AC impedance spectroscopy. UV-vis spectroscopy data indicated directly that ibuprofen could interact with lipid vesicles. In electrochemical experiments, ibuprofen displayed a biphasic behavior on bilayer lipid membrane supported on a glassy carbon electrode. It could stabilize the lipid membrane in low concentration, while it induced defects formation, even removed off bilayer lipid membrane from the surface of the electrode with increasing concentration. The mechanism about the interaction between ibuprofen and supported bilayer lipid membrane was discussed. 相似文献
52.
席静芳 《上海第二工业大学学报》2005,22(Z1):27-32
首先阐明有源滤波器的基本概念和传递函数,然后着重介绍具有低灵敏度的GIC型双运放电路和在较高频率时应用的开关电容滤波器,最后举例说明它们的应用. 相似文献
53.
This paper investigates induced voltage characteristics from an overhead transmission line by applying a method of modeling of induced voltages proposed by the authors. EMTP simulation results obtained by the modeling method agree with analytical results obtained from a well‐known formula. The induced voltages are significantly dependent on the configuration of the overhead line. A horizontal line induces the largest voltage in a gas pipeline, and the voltage induced by a vertical twin‐circuit line is about 20% smaller than that induced by a vertical single‐circuit line. The method is applied to a real pipeline system and the simulation results show reasonable agreement with field test results. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(1): 43–51, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20465 相似文献
54.
55.
The paper presents a derivation of the dynamic impedance of a PV module. At each bias voltage, the general form of the impedance describes a semicircular locus in the complex impedance plane. Intercepts of each impedance locus yield series, shunt and dynamic resistance of a module. Determinations of the dynamic impedance of a x-Si PV module in the dark with five reverse bias voltages and over a frequency range of 1 Hz to 60 kHz are made. The experimental results validate the derived general form of dynamic impedance. 相似文献
56.
Electric charges at the surface of a passive stainless steel are generally considered as concentrated either in the passive film itself, or at the metal/passive film interface, or in the electrical double layer at the film solution interface. Rest potential time dependence after immersion of a passive surface in aqueous electrolytes suggests however that slow processes occur in the onset of the surface charge. Specific experiments, such as streaming potential measurements and electrochemical impedance spectroscopy in a thin electrolyte cell, were carried out for understanding better this phenomenon. An AISI 304 type austenitic stainless steel with polished or bright annealed surface finishes was immersed in NaCl aqueous solutions with various pH and chloride concentrations. The streaming potential time evolution shows two steps: a first rapid one (∼2 min) is attributed to the onset of the surface charge. The second step is much slower (approximately several hours) and possibly due to an interphase layer between the passive film and the solution. Following this idea, the whole kinetics is controlled by cation migration across the interphase when the pH is larger than the isoelectric pH (pHiep), while chloride ions are incorporated in the interphase when pH < pHiep. Impedance measurements allow determining both the kinetics of charge transport and the thin cell conductivity. When glass is used as reference material for the cell walls instead of stainless steel, the Nyquist plots show a high-frequency response. For stainless steel cell walls, a low-frequency response is observed, attributed to a slow charge reorganisation inside the interphase layer. The charge distribution at metal/electrolyte interface is discussed in terms of a gel-like layer which possibly takes place at the passive film/electrolyte interface. 相似文献
57.
高分辨率测井约束地震反演技术在本布图地区的应用 总被引:1,自引:0,他引:1
简要介绍了高分辨率测井约束地震反演技术应遵循的原则及实现步骤,并应用该技术对焉耆盆地本布图背斜构造带进行预测和分析。通过对比分析,反演剖面的分辨率和信噪比有所提高,能较好的反映储层性质的横向变化,预测结果与实际基本符合,说明高分辨率测井约束反演技术在该地区具有一定的实用性。 相似文献
58.
在加工应用试验的基础上。探讨了加工温度、吹胀比、超想线高度及设备对4F0.06AC薄膜适宜的加工条件。 相似文献
59.
近年来,电驱动已成为石油钻机的主要驱动形式,是钻机自动化、智能化的坚实平台。文章就电动钻机的部分工作理论作初步剖析,包括钻机工作机组对电驱动的要求,可控硅直流电驱动和交流变频电驱动的工作原理,直流电动机和交流变频电动机等的特性分析,电动机的四象限运行和能耗制动原理等。 相似文献
60.