全文获取类型
收费全文 | 370篇 |
免费 | 96篇 |
国内免费 | 32篇 |
专业分类
电工技术 | 40篇 |
综合类 | 26篇 |
化学工业 | 74篇 |
金属工艺 | 18篇 |
机械仪表 | 12篇 |
建筑科学 | 29篇 |
矿业工程 | 13篇 |
能源动力 | 12篇 |
轻工业 | 66篇 |
水利工程 | 14篇 |
石油天然气 | 25篇 |
武器工业 | 3篇 |
无线电 | 44篇 |
一般工业技术 | 63篇 |
冶金工业 | 5篇 |
原子能技术 | 1篇 |
自动化技术 | 53篇 |
出版年
2024年 | 12篇 |
2023年 | 27篇 |
2022年 | 49篇 |
2021年 | 65篇 |
2020年 | 35篇 |
2019年 | 26篇 |
2018年 | 38篇 |
2017年 | 31篇 |
2016年 | 25篇 |
2015年 | 41篇 |
2014年 | 30篇 |
2013年 | 27篇 |
2012年 | 20篇 |
2011年 | 16篇 |
2010年 | 16篇 |
2009年 | 14篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 1篇 |
2000年 | 1篇 |
1998年 | 1篇 |
1993年 | 1篇 |
排序方式: 共有498条查询结果,搜索用时 15 毫秒
1.
以园区为研究背景,基于"以热定电"、"以电定热"两种模式,对园区内的综合能源系统进行研究.针对夏季、冬季两个典型日设计了八种方案来对比系统配置液化空气储能与未配置液化空气储能时各子系统输出功率及总成本的变化.结果表明,在园区配置液化空气储能,采用"以热定电"模式运行时经济效益最高且能源损耗量最少.在大暑日,其总成本比未配置液化空气储能的系统降低6.1%.在大寒日,其总成本比未配置液化空气储能的系统总成本降低4.5%.同样配置液化空气储能的情况下,采用"以热定电"模式运行的系统要比"以电定热"模式总成本低.在大暑日总成本降低9.5%,在大寒日,总成本降低4.5%. 相似文献
2.
Sajjad Muhammad Asif Sana Ullah Guan Linlin Jiao Yangjing Jiang Yuhan Zhang Linlin Wen Jia Zhang Shuyu Lin Yuting Zhang Shuangshuang Ding Zhiwei Ren Yang Zhou Xiaowei Hu Wanbiao Liu Zhu 《Journal of Inorganic and Organometallic Polymers and Materials》2021,31(11):4440-4441
Journal of Inorganic and Organometallic Polymers and Materials - The original version of this article unfortunately contained mistakes. In line 9 of the abstract, 5% should read as 2%. The... 相似文献
3.
4.
Tumor Therapy: Bifunctional Platinated Nanoparticles for Photoinduced Tumor Ablation (Adv. Mater. 46/2016) 下载免费PDF全文
5.
Influence maximization of temporal social networks (IMT) is a problem that aims to find the most influential set of nodes in the temporal network so that their information can be the most widely spread. To solve the IMT problem, we propose an influence maximization algorithm based on an improved K-shell method, namely improved K-shell in temporal social networks (KT). The algorithm takes into account the global and local structures of temporal social networks. First, to obtain the kernel value Ks of each node, in the global scope, it layers the network according to the temporal characteristic of nodes by improving the K-shell method. Then, in the local scope, the calculation method of comprehensive degree is proposed to weigh the influence of nodes. Finally, the node with the highest comprehensive degree in each core layer is selected as the seed. However, the seed selection strategy of KT can easily lose some influential nodes. Thus, by optimizing the seed selection strategy, this paper proposes an efficient heuristic algorithm called improved K-shell in temporal social networks for influence maximization (KTIM). According to the hierarchical distribution of cores, the algorithm adds nodes near the central core to the candidate seed set. It then searches for seeds in the candidate seed set according to the comprehensive degree. Experiments show that KTIM is close to the best performing improved method for influence maximization of temporal graph (IMIT) algorithm in terms of effectiveness, but runs at least an order of magnitude faster than it. Therefore, considering the effectiveness and efficiency simultaneously in temporal social networks, the KTIM algorithm works better than other baseline algorithms. 相似文献
6.
7.
红外探测器作为星载偏振探测载荷的核心部件,用于实现短波红外波段辐射偏振信息的光电转换.为保证应用性能,需要对探测器进行精密温控,保证其工作在较低且稳定的温度以降低探测器热噪声和暗电流.本文介绍了一种红外探测器温控系统,采用FPGA控制完成温度信号的采集并输出控制信号,数模转换器控制三极管驱动电流完成半导体制冷器的驱动,采用Bang-Bang和PID复合控制算法完成探测器的精密温控,测试结果表明,温控精度优于±0.1℃,温度稳定时间小于6 min,可将探测器在较短的时间内控制在目标温度范围内,为实现短波红外波段的高精度偏振信息测量提供保障. 相似文献
8.
为得到余甘子核仁油的最优储藏条件,对其氧化稳定性进行研究。通过Rancimat法测定了人工合成抗氧化剂与天然抗氧化剂及增效剂与抗氧化剂的复配对余甘子核仁油氧化诱导时间的影响,考察了金属离子(Fe~(3+)、Fe~(2+)、Zn~(2+)、Cu~(2+))、紫外光照时间、温度对添加复配抗氧化剂的余甘子核仁油氧化诱导时间的影响。结果表明:柠檬酸分别与抗坏血酸棕榈酸酯(AP)和TBHQ复配组合抗氧化效果最为明显;Fe~(3+)、Fe~(2+)以及Cu~(2+)、紫外光照时间和温度均对余甘子核仁油的氧化诱导时间有显著的影响;在25℃条件下,柠檬酸与TBHQ复配组合能将余甘子核仁油的货架期由0.35年延长至1.15年,显著提高了余甘子核仁油的储藏性能,为余甘子核仁油的加工利用提供理论依据。 相似文献
9.
Control of anthracnose rot and quality deterioration in loquat fruit with methyl jasmonate 总被引:2,自引:0,他引:2
Shifeng Cao Yonghua Zheng Zhenfeng Yang Shuangshuang Tang Peng Jin 《Journal of the science of food and agriculture》2008,88(9):1598-1602
BACKGROUND: Loquat (Eriobotrya japonica Lindl.) fruit has a short shelf‐life, mainly due to fungal decay. Current control of postharvest disease of the fruit is mainly dependent on fungicides. However, because of the increasing consumer concern over food safety, there is an urgent need to search for effective alternatives to control disease. The objective of this work was to determine the efficacy of methyl jasmonate (MeJA) in controlling anthracnose rot caused by Colletotrichum acutatum and maintaining quality of loquat fruit. RESULTS: Loquat fruit were treated with 10 µmol L?1 MeJA and wound inoculated with C. acutatum spore suspension of 1.0 × 105 spores mL?1 24 h after treatment, and then stored at 20 °C for 6 days. The percentage of infected wounds showing decay symptom was reduced from 54.4% to 16.7% and the lesion diameter was reduced from 7.26 mm to 4.00 mm by MeJA treatment on the 4th day after inoculation. MeJA treatment induced higher activities of two defense‐related enzymes—chitinase and β‐1,3‐glucanase—during 6 days storage. Meanwhile, the treatment inhibited increases in fruit firmness and internal browning index, and maintained higher extractable juice rate and total soluble solids and titratable acidity contents, thereby delaying the development of flesh leatheriness. CONCLUSION: MeJA treatment effectively inhibited anthracnose rot and maintained quality in loquat fruit. Inhibition of the disease was mainly because of resistance induced in loquat fruit by MeJA. A postharvest application of MeJA could be an alternative to chemical fungicides for control of postharvest disease in loquat fruit. Copyright © 2008 Society of Chemical Industry 相似文献
10.
为有效指导农业温室气体减排政策的制定,本研究分别采用CH4MOD模型和排放因子法估算了2018年长三角地区农作物甲烷(CH4)和氧化亚氮(N2O)排放,并分析其时空分布规律,最终建立了2018年长三角地区农作物1 km×1 km网格化温室气体排放清单.研究结果表明:长三角稻田CH4排放因子为348.54 kg/hm2,农作物N2O排放因子为0.95 kg/hm2,与前人研究结果具有一致性.长三角地区稻田CH4排放为176.9万t(折合约3 714.9万t CO2当量),最主要排放源为单季稻稻田;农作物N2O排放为15114.9 t(折合约450.4万t CO2当量),小麦是主要贡献源.CH4和N2O排放均主要来源于江苏省和安徽省,且集中在4—8月.建议加强对农业温室气体排放的管控,从源头上减少农田碳氮源的输入. 相似文献