全文获取类型
收费全文 | 19063篇 |
免费 | 2434篇 |
国内免费 | 1402篇 |
专业分类
电工技术 | 1555篇 |
技术理论 | 1篇 |
综合类 | 1610篇 |
化学工业 | 2683篇 |
金属工艺 | 1109篇 |
机械仪表 | 1064篇 |
建筑科学 | 1613篇 |
矿业工程 | 460篇 |
能源动力 | 535篇 |
轻工业 | 1677篇 |
水利工程 | 471篇 |
石油天然气 | 865篇 |
武器工业 | 238篇 |
无线电 | 2507篇 |
一般工业技术 | 2597篇 |
冶金工业 | 653篇 |
原子能技术 | 246篇 |
自动化技术 | 3015篇 |
出版年
2024年 | 170篇 |
2023年 | 456篇 |
2022年 | 832篇 |
2021年 | 961篇 |
2020年 | 776篇 |
2019年 | 657篇 |
2018年 | 684篇 |
2017年 | 737篇 |
2016年 | 691篇 |
2015年 | 885篇 |
2014年 | 1039篇 |
2013年 | 1252篇 |
2012年 | 1358篇 |
2011年 | 1398篇 |
2010年 | 1271篇 |
2009年 | 1156篇 |
2008年 | 1076篇 |
2007年 | 1053篇 |
2006年 | 1030篇 |
2005年 | 761篇 |
2004年 | 570篇 |
2003年 | 582篇 |
2002年 | 748篇 |
2001年 | 663篇 |
2000年 | 404篇 |
1999年 | 376篇 |
1998年 | 235篇 |
1997年 | 206篇 |
1996年 | 178篇 |
1995年 | 143篇 |
1994年 | 108篇 |
1993年 | 111篇 |
1992年 | 104篇 |
1991年 | 55篇 |
1990年 | 43篇 |
1989年 | 32篇 |
1988年 | 21篇 |
1987年 | 19篇 |
1986年 | 14篇 |
1985年 | 10篇 |
1984年 | 9篇 |
1983年 | 10篇 |
1982年 | 5篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1965年 | 1篇 |
1959年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Design of a 2-DOF-PID controller using an improved sine–cosine algorithm for load frequency control of a three-area system with nonlinearities 下载免费PDF全文
This paper proposes an improved sine–cosine algorithm (ISCA) based 2-DOF-PID controller for load frequency control. A three-area test system is built for study, while some physical constraints (nonlinearities) are considered for the investigation of a realistic power system. The proposed method is used as the parameter optimizer of the LFC controller in different scenarios. The 2-DOF-PID controllers are used because of their capability of fast disturbance rejection without significant increase of overshoot in set-point tracking. The 2-DOF-PID controllers’ efficacy is observed by examining the responses with the outcomes obtained with PID and FOPID controllers. The simulation results with the suggested scheme are correlated with some of the existing algorithms, such as SCA, SSA, ALO, and PSO in three different scenarios, i.e., a disturbance in two areas, in three areas, and in the presence of physical constraints. In addition, the study is extended to a four-area power system. Statistical analysis is performed using the Wilcoxon Sign Rank Test (WSRT) on 20 independent runs. This confirms the supremacy of the proposed method. 相似文献
22.
高性能罗兰-C接收天线设计 总被引:1,自引:0,他引:1
为了提高罗兰-C磁天线的接收能力,设计了一种顺接串联多层线圈的磁天线。理论推导了顺接串联多层线圈磁天线的信噪比和灵敏度,最终设计的磁天线大小为150 mm×150 mm。远场测试接收到了较高信噪比的罗兰-C信号,在相同信号调理电路条件下,与单层单组线圈的磁天线相比,顺接串联多层线圈的磁天线接收到3.47 V的电压信号,且信噪比高达30.87 dB,灵敏度和信噪比分别提高了82.42%和63.20%。顺接串联多层线圈磁天线提高了罗兰-C磁天线的灵敏度和信噪比,对罗兰-C系统在定位方面的应用具有重要意义。 相似文献
23.
24.
Zixuan Wang Dongzhao Hao Yuefei Wang Jinwu Zhao Jiaxing Zhang Xi Rong Jiaojiao Zhang Jiwei Min Wei Qi Rongxin Su Mingxia He 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(1):2204959
The self-assembly of peptidyl virus-like nanovesicles (pVLNs) composed of highly ordered peptide bilayer membranes that encapsulate the small interfering RNA (siRNA) is reported. The targeting and enzyme-responsive sequences on the bilayer's surface allow the pVLNs to enter cancer cells with high efficiency and control the release of genetic drugs in response to the subcellular environment. By transforming its structure in response to the highly expressed enzyme matrix metalloproteinase 7 (MMP-7) in cancer cells, it helps the siRNA escape from the lysosomes, resulting in a final silencing efficiency of 92%. Moreover, the pVLNs can serve as reconfigurable “Trojan horse” by transforming into membranes triggered by the MMP-7 and disrupting the cytoplasmic structure, thereby achieving synergistic anticancer effects and 96% cancer cell mortality with little damage to normal cells. The pVLNs benefit from their biocompatibility, targeting, and enzyme responsiveness, making them a promising platform for gene therapy and anticancer therapy. 相似文献
25.
针对嵌入式系统芯片SoC开发验证阶段的需求,介绍了一种通用的SoC软硬件协同仿真平台。软件仿真由C/C++和汇编语言编写,硬件仿真基于VMM验证方法学所搭建,SoC设计代码由RTL代码编写而成。将SoC设计代码中的ARM由DSM模型替代,通过VCS编译器将软硬件协同起来进行信息交互,实现一种速度快、真实性高、调试方便的... 相似文献
26.
同一VLAN下的2个物理机房,其中一个机房在使用广播软件教学时会对另一个机房产生干扰,并且学生接受教师屏幕时是被动模式.该文介绍了一种使用VNC远程控制软件,实现学生主动连接教师机并且在2个物理机房同时教学时不产生广播教学干扰的方法 相似文献
27.
28.
通过对教学方法地研究,在项目分解、分组讨论、多媒体应用、游戏代码剖析、网络辅助等方面进行具体地理论和实验教学,使得学生能更好的掌握《数据结构》这门基础课程. 相似文献
29.
Wang JX Liao SH Zhu XH Wang Y Ling CX Ding X Fang YM Zhang XH 《Computer methods and programs in biomedicine》2011,104(3):472-479
This paper presents an intuitive nose surgery planning and simulation system, using 3D laser scan image and lateral X-ray image, to provide high quality prediction of the postoperative appearance, and design the patient specific prosthesis model automatically. After initial registration, the internal surface of soft tissue at the nose region was generated by the statistical data for soft tissue thickness adapted by the individual thickness information from the X-ray image. Then, the sketch contour of the 3D scan data on the lateral X-ray image was modified manually or adjusted automatically according to some aesthetic statistical data, to drive the simulation in real time by the state-of-the-art Laplacian surface deformation method. When satisfied with the 3D postoperative appearance, the deformation was mapped to the internal surface of soft tissue, and the change before and after simulation was utilized to generate the patient specific prosthesis model automatically. The surgeons who used the system confirmed that this planning system is attractive and has potential for daily clinical practice. 相似文献
30.