全文获取类型
收费全文 | 604篇 |
免费 | 33篇 |
国内免费 | 90篇 |
专业分类
电工技术 | 24篇 |
综合类 | 72篇 |
化学工业 | 55篇 |
金属工艺 | 43篇 |
机械仪表 | 54篇 |
建筑科学 | 68篇 |
矿业工程 | 11篇 |
能源动力 | 24篇 |
轻工业 | 13篇 |
水利工程 | 35篇 |
石油天然气 | 48篇 |
武器工业 | 1篇 |
无线电 | 79篇 |
一般工业技术 | 79篇 |
冶金工业 | 40篇 |
原子能技术 | 24篇 |
自动化技术 | 57篇 |
出版年
2024年 | 15篇 |
2023年 | 40篇 |
2022年 | 65篇 |
2021年 | 50篇 |
2020年 | 20篇 |
2019年 | 17篇 |
2018年 | 33篇 |
2017年 | 16篇 |
2016年 | 12篇 |
2015年 | 19篇 |
2014年 | 30篇 |
2013年 | 38篇 |
2012年 | 33篇 |
2011年 | 28篇 |
2010年 | 22篇 |
2009年 | 31篇 |
2008年 | 36篇 |
2007年 | 30篇 |
2006年 | 41篇 |
2005年 | 38篇 |
2004年 | 13篇 |
2003年 | 14篇 |
2002年 | 8篇 |
2001年 | 17篇 |
2000年 | 17篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 6篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有727条查询结果,搜索用时 15 毫秒
1.
2.
1 IntroductionWiththerapiddevelopmentofInternetandmobilecommunications,theresearchonwirelessmobilenetworkshasbecomethenewhotspotinin formationtechnologyfield .Asweknow ,mobileterminals (mobilephone,forexample)arethetooltohelppeopletoaccessanyinformationtheyneedbyanymediaatanytimeandanywhere .However,itissometimesdifficultformobileterminalstoplaysucharolebecauseofthelimitationssuchaslimitedca pacity ,lowpower,andinconvenienceinoperating .So,peoplehopetofindanotherwaytoaccessnet workinformatio… 相似文献
3.
4.
Light detecting and ranging(LiDAR)technology has become an efective way to generate highresolution digital terrain models(DTMs).To generate DTMs,point measurements from non-ground features,such as buildings,vegetation and vehicles,have to be identifed and removed while preserving the terrain points.This paper proposes an efcient mathematical morphology-based multi-level flter to generate DTMs from airborne LiDAR data.Preliminary non-ground points are frst identifed with the characteristics of the multiecho airborne LiDAR data.The localized mathematical morphology opening operations are then immediately applied to the remaining points.By gradually increasing the window size of the flter and using a dynamic critical gradient threshold,the non-ground points are removed,while the ground points are preserved.Eight samples were chosen from eight sites provided with the ISPRS Commission III,Working Group 3,to evaluate the accuracy of our algorithm.Both the qualitative and quantitative experiment analyses show that our morphologybased multi-level flter method achieves promising results,not only in flat urban areas but also in rural areas,especially in preserving complex terrain details,while non-ground spatial objects are removed. 相似文献
5.
移动终端是车辆监控系统的重要组成部分,主要用来接收GPS信号并对其进行处理,然后通过GPRs网络发送给监控中心.本文介绍了一种嵌入式Linux系统平台下,移动终端软件的设计方案及其相关实现. 相似文献
6.
With the expansion of smart grid and Internet of things (IoT) technology, edge computing has a wide variety of applications in these domains. The criteria for real-time monitoring and accuracy are particularly high in the field of online real-time monitoring of electricity lines. Based on edge technology, high-quality real-time monitoring can be performed for transmission lines using image processing techniques. Therefore, we propose an image denoising method, which can learn clean images using a stream-based generative model. The stream model uses a two-stage approach in the network to handle the different training periods of denoising separately. Experimental results show that the proposed method has good denoising performance. 相似文献
7.
According to the factors that confirm the shape of surface, it is classified into two categories: arc surface and curve surface The method to confirm the category of surfaces and the plotting methods are discussed in this paper, which provide guidance for parts plotting. 相似文献
8.
Zhen EY Berna MJ Jin Z Pritt ML Watson DE Ackermann BL Hale JE 《Proteomics. Clinical applications》2007,1(7):661-671
Heart fatty acid binding protein (Fabp3) is a cytosolic protein expressed primarily in heart, and to a lesser extent in skeletal muscle, brain, and kidney. During myocardial injury, the Fabp3 level in serum is elevated rapidly, making it an ideal early marker for myocardial infarction. In this study, an MS‐based selected reaction monitoring method (LC‐SRM) was developed for quantifying Fabp3 in rat serum. Fabp3 was enriched first through an immobilized antibody, and the protein was digested on beads directly. A marker peptide of Fabp3 was quantified using LC‐SRM with a stable isotope‐labeled peptide standard. For six quality control samples with Fabp3 ranging from 0.256 to 25 ng, the average recovery following the procedure was about 73%, and the precision (%CV) between replicates was less than 7%. The Fabp3 concentrations in rat serum peaked 1 h after isoproterenol treatment, and returned to baseline levels 24 h after the dose. Elevated Fabp3 levels were also detected in rats administered with a PPAR α/δ agonist, which has shown to cause skeletal muscle necrosis. Fabp3 can be used as a biomarker for both cardiac and skeletal necroses. The cross‐validation of the LC‐SRM method with an existing ELISA method is described. 相似文献
9.
A novel method for the determination of nickel was established by ultrasonic-assisted cloud point extraction (UA-CPE) prior to flame atomic absorption spectrometry (FAAS) analysis. The nickel reacted with N,N'-bis(salicylidene)-1,2-ethanediamine (BSE) to form hydrophobic chelates, which were extracted into the micelles of alpha-[3,5-dimethyl-1-(2-methylpropyl)hexyl]-omega- poly(oxy-2-ethanediyl) (Tergitol TMN-6). Tergitol TMN-6 was used as green nonionic surfactant. BSE was synthesized and checked by nuclear magnetic resonance (NMR) spectra. The phase diagrams of the binary system, water-surfactant (Tergitol TMN-6), and the ternary systems, water-surfactant-salt, were determined. The effects of experimental conditions including pH of sample solution, concentration of chelating agent and surfactant, ultrasonic power, equilibration temperature and incubation time were evaluated in order to enhance sensitivity of the method. Under the optimal conditions, the calibration graph was linear in the range of 10-500 μg L(-1). The values obtained for the limit of detection and enrichment factor were 1.0 μg L(-1) and 30, respectively. The method was successfully applied to the analysis of nickel in water samples. 相似文献
10.
For characterizing a series augmented railgun launching process,the simulation and experiment were done.In the experiment,only observation of muzzle voltage,current and armature position were insuffici... 相似文献