全文获取类型
收费全文 | 26364篇 |
免费 | 2771篇 |
国内免费 | 1250篇 |
专业分类
电工技术 | 7985篇 |
技术理论 | 2篇 |
综合类 | 2511篇 |
化学工业 | 887篇 |
金属工艺 | 715篇 |
机械仪表 | 1679篇 |
建筑科学 | 1113篇 |
矿业工程 | 1085篇 |
能源动力 | 562篇 |
轻工业 | 250篇 |
水利工程 | 501篇 |
石油天然气 | 482篇 |
武器工业 | 228篇 |
无线电 | 7053篇 |
一般工业技术 | 1016篇 |
冶金工业 | 636篇 |
原子能技术 | 256篇 |
自动化技术 | 3424篇 |
出版年
2024年 | 89篇 |
2023年 | 260篇 |
2022年 | 465篇 |
2021年 | 606篇 |
2020年 | 666篇 |
2019年 | 494篇 |
2018年 | 469篇 |
2017年 | 748篇 |
2016年 | 889篇 |
2015年 | 944篇 |
2014年 | 1678篇 |
2013年 | 1391篇 |
2012年 | 1967篇 |
2011年 | 2085篇 |
2010年 | 1616篇 |
2009年 | 1628篇 |
2008年 | 1637篇 |
2007年 | 1927篇 |
2006年 | 1721篇 |
2005年 | 1431篇 |
2004年 | 1279篇 |
2003年 | 1161篇 |
2002年 | 947篇 |
2001年 | 818篇 |
2000年 | 678篇 |
1999年 | 520篇 |
1998年 | 367篇 |
1997年 | 362篇 |
1996年 | 322篇 |
1995年 | 245篇 |
1994年 | 247篇 |
1993年 | 163篇 |
1992年 | 144篇 |
1991年 | 100篇 |
1990年 | 69篇 |
1989年 | 71篇 |
1988年 | 65篇 |
1987年 | 27篇 |
1986年 | 12篇 |
1985年 | 16篇 |
1984年 | 20篇 |
1983年 | 10篇 |
1982年 | 7篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1958年 | 1篇 |
1956年 | 1篇 |
1951年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Dr. Ying Wang Prof. Dr. Andrew Ewing 《Chembiochem : a European journal of chemical biology》2021,22(5):807-813
Exocytosis plays an essential role in the communication between cells in the nervous system. Understanding the regulation of neurotransmitter release during exocytosis and the amount of neurotransmitter content that is stored in vesicles is of importance, as it provides fundamental insights to understand how the brain works and how neurons elicit a certain behavior. In this minireview, we summarize recent progress in amperometric measurements for monitoring exocytosis in single cells and electrochemical cytometry measurements of vesicular neurotransmitter content in individual vesicles. Important steps have increased our understanding of the different mechanisms of exocytosis. Increasing evidence is firmly establishing that partial release is the primary mechanism of release in multiple cell types. 相似文献
3.
针对传统低压回路电阻测试仪只能在被测设备停电时使用的一大限制,本文提出并设计了一种新型低压回路电阻测试仪。该仪器可在低压设备运行状态下对其回路电阻进行测量,在保证测量精度的前提下减少了设备停电率,大大提高了工作效率。 相似文献
4.
This study proposes that a novel integrated circuit (IC) and system design for renewable energy inverters can harvest renewable energy to power direct current (DC) and alternating current (AC) loads. In addition, an intelligent synthesis and management tool is developed to design the proposed system and to judge the system’s operational maintenance decisions. Finally, a renewable energy inverter’s information is posted to an online system. Users can obtain the proposed system’s information at any time and place. The accurate and superior performance of the proposed IC and system is confirmed by computer simulations and experimental results. 相似文献
5.
6.
本文结合HTH电路的复杂性等特征分析与实际应用现状,研究了HTH电路的具体检测技术方法并对当前热点技术进行对比分析,探讨了HTH电路检测方法的技术发展趋势。 相似文献
7.
An alternative Equivalent Electrical Circuit for Proton Exchange Membrane Fuel Cells is modelled in this study. Both I–V characteristics and H2 consumptions corresponding to generated power under load and no-load conditions are investigated. For this purpose, H2 consumptions and I–V characteristics of three different sized PEMFCs are tested. There is a very good harmony between the model results and measured values (relative error %0.7, %6.4 and %2.5 for FC-A, FC-B and FC-C respectively). In the proposed model current passes only on parallel resistance and not on serial resistance at no-load condition. Thus, a FC with higher parallel resistance should be preferred. Another key output of this study is that based on the proposed model, performance comparison of FCs can be performed with the parameters defined in this work. Proposals made in this study can easily be used for performance analysis of FCs under for both steady state and transient analysis. 相似文献
8.
The 3D structure electromagnetic computation presents several difficulties related to the volume mesh. In fact, the entire volume space must be taken into account even the smallest details. In this article, we propose a formulation based on the reciprocity theorem combined with the generalized equivalent circuit method to model a planar 3D structure with both coaxial and planar excitation. The major advantage of this formulation is the fact to reduce the computational volume into 2D ones in the discontinuity plane. In addition, we focused on the calculation of the discontinuity between the excitation source and the planar structure to determine the exact behavior of the electric coaxial excitation model. The obtained current density, electric field distributions, and the input impedance are presented and discussed in the following sections. An approximately good agreement of input impedance with those obtained by the simulator and measurement is shown. 相似文献
9.
摘 要:针对城市地理信息平台构建过程中存在的数据获取困难、研发成本较高等问题,
引入开源技术,对基于开源数据、开源开发平台与开源工具的城市地理信息平台构建技术进行
研究。所提出的城市地理信息平台由数据模块与可视化模块 2 部分组成。为构建数据模块,由
开源地理信息项目(OSM)获取了建筑与区划数据,并设计了建筑合并算法以提升数据质量。建
筑数据随之基于行政区划分级存储,通过由 ASP. NET 构建的数据接口提供给具体应用。可视
化模块则基于开源地理信息系统(GIS)项目 Cesium 实现,并设计了完善的用户界面。以北京市
为例,完成了原型系统的开发与测试,证实了该技术体系的可行性,通过开源技术降低平台研
发成本,推进城市地理信息平台的研究与应用。 相似文献
10.