全文获取类型
收费全文 | 2088篇 |
免费 | 120篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 30篇 |
综合类 | 4篇 |
化学工业 | 434篇 |
金属工艺 | 25篇 |
机械仪表 | 34篇 |
建筑科学 | 121篇 |
矿业工程 | 4篇 |
能源动力 | 81篇 |
轻工业 | 187篇 |
水利工程 | 14篇 |
石油天然气 | 4篇 |
无线电 | 202篇 |
一般工业技术 | 406篇 |
冶金工业 | 215篇 |
原子能技术 | 19篇 |
自动化技术 | 432篇 |
出版年
2024年 | 3篇 |
2023年 | 19篇 |
2022年 | 32篇 |
2021年 | 58篇 |
2020年 | 31篇 |
2019年 | 48篇 |
2018年 | 50篇 |
2017年 | 44篇 |
2016年 | 49篇 |
2015年 | 64篇 |
2014年 | 83篇 |
2013年 | 116篇 |
2012年 | 97篇 |
2011年 | 155篇 |
2010年 | 148篇 |
2009年 | 109篇 |
2008年 | 127篇 |
2007年 | 106篇 |
2006年 | 97篇 |
2005年 | 88篇 |
2004年 | 67篇 |
2003年 | 71篇 |
2002年 | 72篇 |
2001年 | 34篇 |
2000年 | 38篇 |
1999年 | 45篇 |
1998年 | 55篇 |
1997年 | 26篇 |
1996年 | 36篇 |
1995年 | 26篇 |
1994年 | 33篇 |
1993年 | 33篇 |
1992年 | 10篇 |
1991年 | 17篇 |
1990年 | 11篇 |
1989年 | 7篇 |
1988年 | 10篇 |
1987年 | 4篇 |
1986年 | 8篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 6篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1978年 | 5篇 |
1977年 | 12篇 |
1976年 | 14篇 |
1975年 | 7篇 |
1974年 | 4篇 |
排序方式: 共有2212条查询结果,搜索用时 15 毫秒
1.
Patricia Seoane-Collazo Amparo Romero-Pic Eva Rial-Pensado Laura Liares-Pose nxela Estvez-Salguero Johan Fern Rubn Nogueiras Carlos Diguez Miguel Lpez 《International journal of molecular sciences》2021,22(4)
Several studies have reported that nicotine, the main bioactive component of tobacco, exerts a marked negative energy balance. Apart from its anorectic action, nicotine also modulates energy expenditure, by regulating brown adipose tissue (BAT) thermogenesis and white adipose tissue (WAT) browning. These effects are mainly controlled at the central level by modulation of hypothalamic neuropeptide systems and energy sensors, such as AMP-activated protein kinase (AMPK). In this study, we aimed to investigate the kappa opioid receptor (κOR)/dynorphin signaling in the modulation of nicotine’s effects on energy balance. We found that body weight loss after nicotine treatment is associated with a down-regulation of the κOR endogenous ligand dynorphin precursor and with a marked reduction in κOR signaling and the p70 S6 kinase/ribosomal protein S6 (S6K/rpS6) pathway in the lateral hypothalamic area (LHA). The inhibition of these pathways by nicotine was completely blunted in κOR deficient mice, after central pharmacological blockade of κOR, and in rodents where κOR was genetically knocked down specifically in the LHA. Moreover, κOR-mediated nicotine effects on body weight do not depend on orexin. These data unravel a new central regulatory pathway modulating nicotine’s effects on energy balance. 相似文献
2.
Per Johan Råsmark Čestmír Koňák Petr Štěpánek Christer Elvingson 《Polymer Bulletin》2005,54(4-5):335-342
Summary Dynamic light scattering was used to investigate the dynamics of sodium poly(styrene sulfonate) and fully neutralized poly(acrylic acid) gels as a function of the degree of swelling and weight ratio of cross-linking agent. It was shown that the collective diffusion coefficient increases with increasing degree of swelling and that the diffusion coefficient shows stronger concentration dependence than predicted by scaling arguments. For gel samples measured at the swelling equilibrium, the diffusion coefficient increases with increasing gel concentration for both gel systems. 相似文献
3.
Broersen P.M.T. de Waele S. Bos R. 《IEEE transactions on instrumentation and measurement》2004,53(4):981-986
Time series solutions for spectral analysis in missing data problems use reconstruction of the missing data, or a maximum likelihood approach that analyzes only the available measured data. Maximum likelihood estimation yields the most accurate spectra. An approximate maximum likelihood algorithm is presented that uses only previous observations falling in a finite interval to compute the likelihood, instead of all previous observations. The resulting nonlinear estimation algorithm requires no user-provided initial solution, is suited for order selection, and can give very accurate spectra even if less than 10% of the data remains. 相似文献
4.
5.
Gert van der Horn Johan H. Huijsing 《Analog Integrated Circuits and Signal Processing》1997,14(3):207-222
In many applications electronic sensors are used toimprove performance and reliability of measurement systems. Suchsensors should provide a correct transfer from the physical signalto be measured to the electrical output signal. One importantstep to achieve this, is to calibrate each sensor by applyingdifferent reference input signals and adjusting the sensor transferaccordingly. Besides expensive reference equipment the calibrationprocess takes much time and attention per individual sensor,which means a considerable increase in sensor production costs.By including at the sensor or sensor interface chip a programmablecalibration facility the calibration of such smart sensors caneasily be automated and can be executed for a batch of sensorsat a time, thus minimizing the calibration time and costs. Thispaper presents a calibration method and options for integrationin the smart sensor concept, in hardware as well as in software.An advantage of the proposed method is that it does not needa large matrix of calibration data, which needs to be storedin a look-up table or converted into a correction formula, butinstead it uses a step-by-step approach to correct the sensortransfer at each calibration measurement until the error is sufficientlysmall. 相似文献
6.
Chen L. Crnic M. Zonghe Lai Johan Liu 《Electronics Packaging Manufacturing, IEEE Transactions on》2002,25(4):273-278
Liquid crystal polymer (LCP) has potentially a very wide application as substrate material in electronic packaging applications because of its unique advantages. The work in this paper was performed to realize the metallization of LCP for the purpose of board fabrication, and to study the adhesion between deposited copper and LCP. A homogenous electroless plated copper layer on LCP with 4 to 5 /spl mu/m thickness was achieved, while it increased up to 40 /spl mu/m with the subsequent electroplating. The timescale of etching, deposit ion rate, and pH value were gradually changing during the plating process and the influences on copper layer quality were investigated. The adhesion force of the copper-LCP layer system was measured by a shear-off-method. Scanning electron microscopy (SEM) was used to check the surface morphology after etching and the interface after shearing on both the backside of the copper layer and the LCP side. The relationship between the shear-off adhesion of copper and the time of chemical etching before plating was examined, and the optimal etching time is discussed. Heat treatment after plating was used, and it was shown that this significantly improved the adhesion strength. 相似文献
7.
Danil Van Nieuwenhove Ward van der Tempel Riemer Grootjans Johan Stiens Maarten Kuijk 《IEEE sensors journal》2007,7(3):317-318
A current assisted photonic demodulator for use as a pixel in a 3-D time-of-flight imager shows nearly 100% static demodulator contrast and is operable beyond 30 MHz. An integrated tunable sensitivity control is also presented for increasing the distance measurement range and avoiding unwanted saturation during integration periods. This is achieved by application of a voltage on a dedicated drain tap showing a quenching of sensor sensitivity to below 1% 相似文献
8.
This article argues that it is not uncommon for people forming justice judgments to lack information that is most relevant in the particular situation. In information-uncertain conditions, people may therefore construct justice judgments by relying on how they feel about the events they have encountered, and justice judgments may hence be strongly influenced by affect information. Findings show that in information-uncertain conditions, the affective states that people had been in prior and unrelated to the justice event indeed strongly influenced their justice judgments. These findings thus reveal that in situations of information uncertainty, people's judgments of justice can be very subjective, susceptible to affective states that have no logical relationship with the justice judgments they are constructing. Implications for the social psychology of justice and the literature on social cognition and affect are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
9.
Johan Gard 《现代电信科技》2002,(12):27-28
分层式体系结构简介 WCDMA的分层式体系结构主要负责媒体网关(MGW)的分配和移动交换中心(MSC)服务器的集中管理.它具有分布式交换功能,并集中进行运营维护和呼叫控制,可大大降低运营开销. 相似文献
10.
Johan M. Thevelein 《Yeast (Chichester, England)》1994,10(13):1753-1790