全文获取类型
收费全文 | 1554篇 |
免费 | 85篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 24篇 |
综合类 | 7篇 |
化学工业 | 318篇 |
金属工艺 | 35篇 |
机械仪表 | 43篇 |
建筑科学 | 77篇 |
矿业工程 | 1篇 |
能源动力 | 114篇 |
轻工业 | 154篇 |
水利工程 | 17篇 |
石油天然气 | 21篇 |
无线电 | 184篇 |
一般工业技术 | 308篇 |
冶金工业 | 58篇 |
原子能技术 | 7篇 |
自动化技术 | 274篇 |
出版年
2024年 | 3篇 |
2023年 | 36篇 |
2022年 | 84篇 |
2021年 | 118篇 |
2020年 | 73篇 |
2019年 | 76篇 |
2018年 | 78篇 |
2017年 | 80篇 |
2016年 | 69篇 |
2015年 | 54篇 |
2014年 | 68篇 |
2013年 | 142篇 |
2012年 | 65篇 |
2011年 | 99篇 |
2010年 | 68篇 |
2009年 | 67篇 |
2008年 | 64篇 |
2007年 | 50篇 |
2006年 | 46篇 |
2005年 | 40篇 |
2004年 | 41篇 |
2003年 | 31篇 |
2002年 | 19篇 |
2001年 | 14篇 |
2000年 | 13篇 |
1999年 | 12篇 |
1998年 | 15篇 |
1997年 | 13篇 |
1996年 | 12篇 |
1995年 | 13篇 |
1994年 | 10篇 |
1993年 | 12篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 7篇 |
1987年 | 2篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有1642条查询结果,搜索用时 31 毫秒
1.
Significant emergency measures should be taken until an emergency event occurs. It is understood that the emergency is characterized by limited time and information, harmfulness and uncertainty, and decision-makers are always critically bound by uncertainty and risk. This paper introduces many novel approaches to addressing the emergency situation of COVID-19 under spherical fuzzy environment. Fundamentally, the paper includes six main sections to achieve appropriate and accurate measures to address the situation of emergency decision-making. As the spherical fuzzy set (FS) is a generalized framework of fuzzy structure to handle more uncertainty and ambiguity in decision-making problems (DMPs). First, we discuss basic algebraic operational laws (AOLs) under spherical FS. In addition, elaborate on the deficiency of existing AOLs and present three cases to address the validity of the proposed novel AOLs under spherical fuzzy settings. Second, we present a list of Einstein aggregation operators (AgOp) based on the Einstein norm to aggregate uncertain information in DMPs. Thirdly, we are introducing two techniques to demonstrate the unknown weight of the criteria. Fourthly, we develop extended TOPSIS and Gray relational analysis approaches based on AgOp with unknown weight information of the criteria. In fifth, we design three algorithms to address the uncertainty and ambiguity information in emergency DMPs. Finally, the numerical case study of the novel carnivorous (COVID-19) situation is provided as an application for emergency decision-making based on the proposed three algorithms. Results explore the effectiveness of our proposed methodologies and provide accurate emergency measures to address the global uncertainty of COVID-19. 相似文献
2.
3.
Multiple degrees‐of‐freedom (multi‐DOF) cell orientation control is a vital important technique involved in single cell surgery applications. Currently, few studies have been performed toward automation of multi‐DOF cell orientation control using robotically controlled optical tweezers. In this paper, a robust control framework is developed to perform multi‐DOF cell rotational control with consideration of model uncertainties and external disturbances. Both simulation and experimental studies are presented to illustrate the performance of the proposed control strategy. The main contributions of this work lie in that this is the first time to develop a unified framework to achieve multi‐DOF cell orientation control without the need for accurate dynamic model parameters and/or any knowledge about uncertainty characteristic, which greatly enhances the robustness of the overall system. 相似文献
4.
Muhammad Zafar Mushtaq Ahmad Shazia Sultana Lubna Adnan Amin Hafiz Muhammad Naseer Zafar Jamal Sheikh Zain Ul Abidin Sajid Mehmood Amir Shehzad Khan 《Microscopy research and technique》2019,82(5):550-557
The use of quality control tool for authentication of Jadwar (Delphinium denudatum Wall. ex Hook.f. & Thomson), a folk herbal drug used for the treatment of different ailments, was studied. People face problems of adulteration for this drug at global, regional, national and local levels. Two different plant species are commercially marketed in the Indo‐Pak Subcontinent under the same trade name of Jadwar. One is D. denudatum Wall. ex Hook.f. & Thomson and the other is Aconitum heterophyllum Wall. ex Royle. To focus on this problem, a marketable available drug sample of Jadwar was authenticated by using basic microscopy tools (LM) and advanced chemo‐taxonomic markers. Authentication, quality and standardization of this drug was achieved using morphology, organoleptography, UV and IR analyses, scanning electron microscopy of pollen and anatomical investigations. The techniques used for authentication marked the clear difference between the studied plants. Microscopic studies, chemotaxonomic investigation and other techniques used in this project provided the basis for the authentication of this species. 相似文献
5.
6.
In this report, praseodymium hydroxide Pr(OH)3 nanowires with different aspect ratios (length to diameter ratios) were synthesized by a facile hydrothermal approach. The variations in alkali concentration during synthesis are found to form different aspect ratios of nanowires. The X-ray diffraction and Raman spectroscopy analysis demonstrate the absence of any impurity phases in as-prepared materials. Subsequently, photocatalytic activities of as-prepared nanowires were evaluated by the degradation of methyl orange (MO). Our findings reveal that the nanowires with larger aspect ratios have higher photocatalytic efficiency than the smaller aspect ratio samples. X-ray photospectroscopy investigations reveal that the samples with higher aspect ratio are found to exhibit more oxygen vacancies as compared to lower aspect ratio samples. The enhanced photocatalytic activities can be attributed to the presence of higher percentage of active crystal facet (100), higher concentration of defects densities and narrower band gap. Thus, Pr(OH)3 nanowires can be considered as a potential candidate for the application of wastewater treatment and related technologies. 相似文献
7.
Predicting catastrophic temperature changes based on past events via a CNN-LSTM regression mechanism
Yusuf Syed Adnan Alshdadi Abdulrahman A. Alassafi Madini O. AlGhamdi Rayed Samad Abdul 《Neural computing & applications》2021,33(15):9775-9790
Neural Computing and Applications - The modelling and prediction of extreme temperature changes in enclosed compartments is a domain with applications ranging from residential fire alarms,... 相似文献
8.
Bukhari Muhammad Adnan Ahmad Zahoor Ashraf M. Yasin Afzal Muhammad Nawaz Fahim Nafees Muhammad Jatoi Wajid Nasim Malghani Naveed Aslam Shah Adnan Noor Manan Abdul 《SILICON》2021,13(12):4757-4772
Silicon - Feeling prone to stress differs with plant production stage, water scarcity near commencement of grain filling phase has a significant reduced grain yield through fewer endosperm and sink... 相似文献
9.
Adnan Tasdemir Buse Bulut Kopuklu Ahmet Can Kirlioglu Selmiye Alkan Gursel Alp Yurum 《International Journal of Hydrogen Energy》2021,46(21):11865-11877
A straightforward, one-step route has been established to fabricate reduced- (rGO) and nitrogen-doped reduced graphene oxide (NrGO) with remarkable lithium-ion storage properties. The graphene oxide (GO) was synthesized as starting material by improved Hummers’ method. Thereafter, thermally annealing GO with NH3 at elevated temperature to synthesize NrGO was yielded a more open structure with nitrogen sites suitable for enhanced Li intercalation. NrGO exhibited a reversible capacity of 240 mAhg?1 at 10 Ag-1 after 500 cycles with 90% capacity retention, which is the best result achieved among graphene oxide-based anodes at this current density. In contrast to rGO, NrGO cells exhibited a gradually increasing capacity profile, reaching up to 114% of the initial capacity at 0.1, 2, and 10 Ag-1 current densities. Results showed that high occupancy of pyridinic N within NrGO enhanced battery performance and cell kinetics upon cycling which offers long-time operability at high current density. 相似文献
10.