全文获取类型
收费全文 | 3880篇 |
免费 | 655篇 |
国内免费 | 796篇 |
专业分类
电工技术 | 341篇 |
综合类 | 669篇 |
化学工业 | 178篇 |
金属工艺 | 105篇 |
机械仪表 | 211篇 |
建筑科学 | 41篇 |
矿业工程 | 18篇 |
能源动力 | 168篇 |
轻工业 | 97篇 |
水利工程 | 8篇 |
石油天然气 | 31篇 |
武器工业 | 22篇 |
无线电 | 1636篇 |
一般工业技术 | 233篇 |
冶金工业 | 58篇 |
原子能技术 | 16篇 |
自动化技术 | 1499篇 |
出版年
2024年 | 15篇 |
2023年 | 185篇 |
2022年 | 223篇 |
2021年 | 223篇 |
2020年 | 241篇 |
2019年 | 203篇 |
2018年 | 204篇 |
2017年 | 218篇 |
2016年 | 212篇 |
2015年 | 218篇 |
2014年 | 457篇 |
2013年 | 530篇 |
2012年 | 737篇 |
2011年 | 795篇 |
2010年 | 429篇 |
2009年 | 139篇 |
2008年 | 75篇 |
2007年 | 59篇 |
2006年 | 42篇 |
2005年 | 16篇 |
2004年 | 11篇 |
2003年 | 10篇 |
2002年 | 16篇 |
2001年 | 17篇 |
2000年 | 9篇 |
1999年 | 11篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 6篇 |
1995年 | 8篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有5331条查询结果,搜索用时 156 毫秒
11.
1-read/1-write (1R1W) register file (RF) is a popular memory configuration in modern feature rich SoCs requiring significant amount of embedded memory. A memory compiler is constructed using the 8T RF bitcell spanning a range of instances from 32 b to 72 Kb. An 8T low-leakage bitcell of 0.106 μm2 is used in a 14 nm FinFET technology with a 70 nm contacted gate pitch for high-density (HD) two-port (TP) RF memory compiler which achieves 5.66 Mb/mm2 array density for a 72 Kb array which is the highest reported density in 14 nm FinFET technology. The density improvement is achieved by using techniques such as leaf-cell optimization (eliminating transistors), better architectural planning, top level connectivity through leaf-cell abutment and minimizing the number of unique leaf-cells. These techniques are fully compatible with memory compiler usage over the required span. Leakage power is minimized by using power-switches without degrading the density mentioned above. Self-induced supply voltage collapse technique is applied for write and a four stack static keeper is used for read Vmin improvement. Fabricated test chips using 14 nm process have demonstrated 2.33 GHz performance at 1.1 V/25 °C operation. Overall Vmin of 550 mV is achieved with this design at 25 °C. The inbuilt power-switch improves leakage power by 12x in simulation. Approximately 8% die area of a leading 14 nm SoC in commercialization is occupied by these compiled RF instances. 相似文献
12.
13.
《钢铁研究学报(英文版)》2006
Pulsed Field Magnetometers (PFMs) offer a method for high speed full loop characterisation of hard magnetic materials. As there is no dependency on iron to close a circuit, the repeatability of the technique is good. By utilising Peltier effect techniques to control the temperature of the measurement coil systems employed in a Pulsed Field Magnetometer, the level of repeatability of measurements can be significantly improved. 相似文献
14.
对某工厂废水处理用液压柱塞泵的弹簧座进行了受力分析、强度计算和金相检验,找出了弹簧座内表面产生晶间腐蚀的原因和解决的方法. 相似文献
15.
《Biomass & bioenergy》2006,30(8-9):803-808
The papermaking properties of 22 pure and hybrid poplars are being evaluated in an on-going investigation. Twenty of the poplars were harvested after 7.5 years from three different sites in the Midwestern and North Central US. The other 2 poplars survived at only two of three sites (64 total samples). The Crandon hybrid had the highest growth rate (t ha−1 y−1) and wood density (both averaged across the 3 sites). This poplar had a high cellulose content (compared to the average), a low lignin content and produced bleached kraft fibers at a high yield (wt.% on wood chips). Further, this poplar responded very well to kraft pulping and oxygen delignification and bleached to the highest final brightness ever observed in our laboratory (94.5% Elrepho). It also produced an 18 kappa number unbleached pulp with <0.5% rejects in only two-thirds the time required for sugar maple (Acer saccharum).We also report on clone 220-5 that had the highest area-weighted average microfibril angle. Pulps from this poplar had excellent tensile properties and further improvements are expected with 1–2 years of additional growth that should result in a small, but significant increase in average fiber length. Some results are also presented for clone 313.55 and aspen (Populus tremuloides) to demonstrate the many substantial benefits that can be accrued from proper wood selection. 相似文献
16.
压电陶瓷驱动电源是压电陶瓷微位移器应用中的关键部件。PA85是一种高电压、高功率MOSFET的带宽运算放大器,采用双电源供电,输出电流高达200mA,输出电压更可高达±215V。该文详细介绍了基于PA85的一种电源复合放大器的设计及仿真,通过对各项性能指标的仿真表明,该驱动电源具有精度高、分辨率高、稳定性好、纹波小和电路结构简单等优点。 相似文献
17.
为了减少传统微波功率测量中由于热损耗所带来的测量误差,本文中应用一种对数二极管检波电路设计了一种小型化的微波功率探头。同时由于在输入端加入了仿真优化的匹配网络,该探头在100MHz-3GHz驻波比得到了明显改善。最终测试结果表明动态范围大于60dB。 相似文献
18.
19.
20.