全文获取类型
收费全文 | 39302篇 |
免费 | 3500篇 |
国内免费 | 1848篇 |
专业分类
电工技术 | 2304篇 |
技术理论 | 2篇 |
综合类 | 2903篇 |
化学工业 | 6414篇 |
金属工艺 | 2041篇 |
机械仪表 | 2498篇 |
建筑科学 | 3166篇 |
矿业工程 | 1240篇 |
能源动力 | 1235篇 |
轻工业 | 3169篇 |
水利工程 | 766篇 |
石油天然气 | 2345篇 |
武器工业 | 301篇 |
无线电 | 4119篇 |
一般工业技术 | 4380篇 |
冶金工业 | 1776篇 |
原子能技术 | 451篇 |
自动化技术 | 5540篇 |
出版年
2024年 | 72篇 |
2023年 | 658篇 |
2022年 | 990篇 |
2021年 | 1511篇 |
2020年 | 1222篇 |
2019年 | 1019篇 |
2018年 | 1165篇 |
2017年 | 1235篇 |
2016年 | 1187篇 |
2015年 | 1528篇 |
2014年 | 2010篇 |
2013年 | 2405篇 |
2012年 | 2572篇 |
2011年 | 2876篇 |
2010年 | 2510篇 |
2009年 | 2434篇 |
2008年 | 2386篇 |
2007年 | 2170篇 |
2006年 | 2088篇 |
2005年 | 1869篇 |
2004年 | 1310篇 |
2003年 | 1250篇 |
2002年 | 1329篇 |
2001年 | 1149篇 |
2000年 | 1003篇 |
1999年 | 907篇 |
1998年 | 702篇 |
1997年 | 649篇 |
1996年 | 547篇 |
1995年 | 437篇 |
1994年 | 384篇 |
1993年 | 264篇 |
1992年 | 223篇 |
1991年 | 148篇 |
1990年 | 118篇 |
1989年 | 60篇 |
1988年 | 86篇 |
1987年 | 45篇 |
1986年 | 32篇 |
1985年 | 20篇 |
1984年 | 16篇 |
1983年 | 13篇 |
1982年 | 16篇 |
1981年 | 11篇 |
1980年 | 10篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1961年 | 1篇 |
1959年 | 2篇 |
1951年 | 1篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
3.
Wireless Networks - With the dynamic voltage scaling (DVS) technology, the terminal node (TN) can dynamically adjust its computational speed, thus providing a new way to save energy during task... 相似文献
4.
Keran Su Kim Huey Ee Jingcan Sun Shao Quan Liu Benjamin Lassabliere Ulrich Feiter Yunle Huang Rui Min Vivian Goh Aileen Pua Bin Yu 《International Journal of Food Science & Technology》2022,57(3):1666-1678
The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min−1 of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study. 相似文献
5.
Neural Processing Letters - This paper is concerned with topology identification of stochastic multi-weighted complex networks based on adaptive synchronization. Different from previous work,... 相似文献
6.
7.
Journal of Materials Science - The CsPbBr3/Cs4PbBr6 perovskite composite material has received wide attention due to its good stability and photoelectric properties, and it is promising to appear... 相似文献
8.
Chu Shipeng Zhang Tuqiao Zhou Xinhong Yu Tingchao Shao Yu 《Water Resources Management》2022,36(2):491-505
Water Resources Management - Real-time modeling of a water distribution system (WDS) is a critical step for the control and operation of such systems. The nodal water demand, as the most important... 相似文献
9.
Farzaneh Khorasani Morteza Mohammadi Zanjireh Mahdi Bahaghighat Qin Xin 《计算机系统科学与工程》2022,40(3):1085-1098
With a sharp increase in the information volume, analyzing and retrieving this vast data volume is much more essential than ever. One of the main techniques that would be beneficial in this regard is called the Clustering method. Clustering aims to classify objects so that all objects within a cluster have similar features while other objects in different clusters are as distinct as possible. One of the most widely used clustering algorithms with the well and approved performance in different applications is the k-means algorithm. The main problem of the k-means algorithm is its performance which can be directly affected by the selection in the primary clusters. Lack of attention to this crucial issue has consequences such as creating empty clusters and decreasing the convergence time. Besides, the selection of appropriate initial seeds can reduce the cluster’s inconsistency. In this paper, we present a new method to determine the initial seeds of the k-mean algorithm to improve the accuracy and decrease the number of iterations of the algorithm. For this purpose, a new method is proposed considering the average distance between objects to determine the initial seeds. Our method attempts to provide a proper tradeoff between the accuracy and speed of the clustering algorithm. The experimental results showed that our proposed approach outperforms the Chithra with 1.7% and 2.1% in terms of clustering accuracy for Wine and Abalone detection data, respectively. Furthermore, achieved results indicate that comparing with the Reverse Nearest Neighbor (RNN) search approach, the proposed method has a higher convergence speed. 相似文献
10.
随着计算机技术的快速发展,虚拟仿真技术越发成熟,在教学中的应用越来越广泛.与传统线下实验教学模式相比,虚拟仿真技术具有安全无害,覆盖面广等优点,可以弥补传统实验教学模式中一些不足.本文主要以水银的处理实验为例,展示了虚拟仿真技术在危险性实验教学中的优势,为实验教学知识体系的完整性提供一个有力支持. 相似文献