收费全文 | 3975篇 |
免费 | 176篇 |
国内免费 | 26篇 |
电工技术 | 79篇 |
综合类 | 4篇 |
化学工业 | 832篇 |
金属工艺 | 114篇 |
机械仪表 | 78篇 |
建筑科学 | 71篇 |
矿业工程 | 2篇 |
能源动力 | 208篇 |
轻工业 | 205篇 |
水利工程 | 28篇 |
石油天然气 | 29篇 |
无线电 | 481篇 |
一般工业技术 | 962篇 |
冶金工业 | 398篇 |
原子能技术 | 17篇 |
自动化技术 | 669篇 |
2023年 | 51篇 |
2022年 | 110篇 |
2021年 | 146篇 |
2020年 | 128篇 |
2019年 | 123篇 |
2018年 | 171篇 |
2017年 | 157篇 |
2016年 | 162篇 |
2015年 | 101篇 |
2014年 | 149篇 |
2013年 | 275篇 |
2012年 | 200篇 |
2011年 | 258篇 |
2010年 | 191篇 |
2009年 | 200篇 |
2008年 | 175篇 |
2007年 | 141篇 |
2006年 | 114篇 |
2005年 | 103篇 |
2004年 | 78篇 |
2003年 | 81篇 |
2002年 | 65篇 |
2001年 | 63篇 |
2000年 | 54篇 |
1999年 | 41篇 |
1998年 | 81篇 |
1997年 | 73篇 |
1996年 | 51篇 |
1995年 | 53篇 |
1994年 | 50篇 |
1993年 | 48篇 |
1992年 | 27篇 |
1991年 | 27篇 |
1990年 | 24篇 |
1989年 | 17篇 |
1988年 | 26篇 |
1987年 | 23篇 |
1986年 | 18篇 |
1985年 | 35篇 |
1984年 | 32篇 |
1983年 | 25篇 |
1982年 | 23篇 |
1981年 | 21篇 |
1980年 | 24篇 |
1979年 | 15篇 |
1977年 | 21篇 |
1976年 | 32篇 |
1975年 | 17篇 |
1974年 | 14篇 |
1973年 | 18篇 |
With the advancement of image acquisition devices and social networking services, a huge volume of image data is generated. Using different image and video processing applications, these image data are manipulated, and thus, original images get tampered. These tampered images are the prime source of spreading fake news, defaming the personalities and in some cases (when used as evidence) misleading the law bodies. Hence before relying totally on the image data, the authenticity of the image must be verified. Works of the literature are reported for the verification of the authenticity of an image based on noise inconsistency. However, these works suffer from limitations of confusion between edges and noise, post-processing operation for localization and need of prior knowledge about an image. To handle these limitations, a noise inconsistency-based technique has been presented here to detect and localize a false region in an image. This work consists of three major steps of pre-processing, noise estimation and post-processing. For the experimental purpose two, publicly available datasets are used. The result is discussed in terms of precision, recall, accuracy and f1-score on the pixel level. The result of the presented work is also compared with the recent state-of-the-art techniques. The average accuracy of the proposed work on datasets is 91.70%, which is highest among state-of-the-art techniques.
相似文献Estimation of terrestrial water budget at global and regional scales are essential for efficient agricultural water management, flood predictions, and, hydrological modeling. In hydrological modeling, it is a challenging task to quantify the major hydrological components like runoff, evapotranspiration (ET), and total water storage (TWS) due to improper and limited availability of detailed meteorological datasets. Furthermore, there has been no consensus to answer a-decade-long critical question that a less data-intensive models can be an alternate to robust data-intensive models in data scarce conditions. This study aims at multi-model approach over the single models usage for representing the hydrological behaviour in the Kangsabati River Basin (KRB), India. It is done by applying the standard model selection criteria over various hydrological models. Two hydrological models are selected, a semi- distributed model, Variable Infiltration Capacity (VIC-3 L), and a conceptually lumped model, Identification of unit Hydrograph and Component flows from Rainfall, Evapotranspiration and Streamflow (IHACRES). Both models were calibrated against the observed daily discharge at the KRB outlet for the period of 2001–2006 and validated for 2008–2010. The results show that both VIC-3 L and IHACRES produce reasonable runoff estimates at daily and monthly time scale in the KRB. The ET estimates show that VIC-3 L and IHACRES captured the seasonal variations with the percent change of 0.4% and 6.6% respectively. As IHACRES is simpler, parsimonious, fewer parameters, and better performances, it can be useful for hydrological modeling in data-scarce regions.
相似文献Hydrological responses corresponding to the agricultural land use alterations are critical for planning crop management strategies, water resources management, and environmental evaluations. However, accurate estimation and evaluation of these hydrological responses are restricted by the limited availability of detailed crop classification in land use and land cover. An innovative approach using state-of-the-art Variable Infiltration Capacity (VIC) model is utilized by setting up the crop-specific vegetation parameterization and analyse the effect of uniform and heterogeneous agricultural land use over the hydrological responses of the basin, in the Kangsabati River Basin (KRB). Thirteen year simulations (1998–2010) based on two different scenarios i.e., single-crop in agricultural land use (SC-ALU) and multi-crop in agricultural land use (MC-ALU) patterns are incorporated in the model and calibrated (1998–2006) and validated (2007–2010) for the streamflow at Reservoir and Mohanpur in the KRB. The results demonstrated that the VIC model improved the estimates of hydrological components, especially surface runoff and evapotranspiration (ET) at daily and monthly timescales corresponding to MC-ALU than SC-ALU (NSC?>?0.7). Grid-scale ET estimates are improved after incorporating heterogeneous agricultural land use (NSC?>?0.55 and R2?>?0.55) throughout the period of 1998–2010. This study improves our understanding on how the change in agricultural land use in the model settings alters the basin hydrological characteristics, and to provide model-based approaches for best management practices in irrigation scheduling, crop water requirement, and management strategies in the absence of flux towers, eddy covariance, and lysimeters in the basin.
相似文献