全文获取类型
收费全文 | 245篇 |
免费 | 10篇 |
专业分类
化学工业 | 56篇 |
金属工艺 | 3篇 |
机械仪表 | 6篇 |
建筑科学 | 10篇 |
能源动力 | 3篇 |
轻工业 | 23篇 |
水利工程 | 2篇 |
石油天然气 | 2篇 |
无线电 | 11篇 |
一般工业技术 | 39篇 |
冶金工业 | 37篇 |
自动化技术 | 63篇 |
出版年
2023年 | 6篇 |
2022年 | 13篇 |
2021年 | 21篇 |
2020年 | 6篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 7篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 13篇 |
2011年 | 20篇 |
2010年 | 6篇 |
2009年 | 13篇 |
2008年 | 16篇 |
2007年 | 5篇 |
2006年 | 8篇 |
2005年 | 14篇 |
2004年 | 10篇 |
2003年 | 3篇 |
2002年 | 7篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 4篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1986年 | 1篇 |
排序方式: 共有255条查询结果,搜索用时 0 毫秒
251.
Rumiana Tzoneva Irina Georgieva Natasha Ivanova Veselina Uzunova Zlatina Nenchovska Sonia Apostolova Tzveta Stoyanova Jana Tchekalarova 《International journal of molecular sciences》2021,22(23)
One of the pathological hallmarks of Alzheimer’s disease (AD) associated with its progression that contributes to β-amyloid (Aβ) generation is oxidative stress (OS). Clinical data suggest that melatonin is a potent antioxidant that might be effective in the adjunctive therapy of this neurodegenerative disease. The present study aimed to explore the role of melatonin on behavioral changes and markers of OS in three rat models, namely, pinealectomy (pin) model of melatonin deficit, intracerebroventricular (icv)Aβ1-42 model of AD, and combination of both pin and Aβ1-42 model (pin+icvAβ1-42). The chronic injection with vehicle/melatonin (50 mg/kg, i.p. for 40 days) started on the same day of sham/pin and icv vehicle/Aβ1-42 infusion procedures. Anxiety in the open field and the elevated plus-maze test and cognitive responses in the object recognition test were tested between the 30th–35th day after the surgical procedures. Markers of OS in the frontal cortex (FC) and hippocampus were detected by the ELISA method. Melatonin treatment corrected the exacerbated anxiety response only in the pin+icvAβ1-42 model while it alleviated the cognitive impairment in the three models. Pinealectomy disturbed the antioxidant system via enhanced SOD activity and decreased GSH levels both in the FC and hippocampus. The Aβ1-42 model decreased the SOD activity in the FC and elevated the MDA level in the two brain structures. The pin+icvAβ1-42 model impaired the antioxidant system and elevated lipid peroxidation. Melatonin supplementation restored only the elevated MDA level of icvAβ1-42 and pin+icvAβ1-42 model in the hippocampus. In conclusion, our study reveals that the pin+icvAβ1-42 rat model triggers more pronounced anxiety and alterations in markers of OS that may be associated with melatonin deficit concomitant to icvAβ1-42-induced AD pathology. 相似文献
252.
José Escorcia-Gutierrez Roosvel Soto-Diaz Natasha Madera Carlos Soto Francisco Burgos-Florez Alexander Rodríguez Romany F. Mansour 《计算机系统科学与工程》2023,46(2):1337-1353
Computer-aided diagnosis (CAD) models exploit artificial intelligence (AI) for chest X-ray (CXR) examination to identify the presence of tuberculosis (TB) and can improve the feasibility and performance of CXR for TB screening and triage. At the same time, CXR interpretation is a time-consuming and subjective process. Furthermore, high resemblance among the radiological patterns of TB and other lung diseases can result in misdiagnosis. Therefore, computer-aided diagnosis (CAD) models using machine learning (ML) and deep learning (DL) can be designed for screening TB accurately. With this motivation, this article develops a Water Strider Optimization with Deep Transfer Learning Enabled Tuberculosis Classification (WSODTL-TBC) model on Chest X-rays (CXR). The presented WSODTL-TBC model aims to detect and classify TB on CXR images. Primarily, the WSODTL-TBC model undergoes image filtering techniques to discard the noise content and U-Net-based image segmentation. Besides, a pre-trained residual network with a two-dimensional convolutional neural network (2D-CNN) model is applied to extract feature vectors. In addition, the WSO algorithm with long short-term memory (LSTM) model was employed for identifying and classifying TB, where the WSO algorithm is applied as a hyperparameter optimizer of the LSTM methodology, showing the novelty of the work. The performance validation of the presented WSODTL-TBC model is carried out on the benchmark dataset, and the outcomes were investigated in many aspects. The experimental development pointed out the betterment of the WSODTL-TBC model over existing algorithms. 相似文献
253.
254.
Dr. Nicholas D. J. Yates Dr. Natasha E. Hatton Dr. Martin A. Fascione Dr. Alison Parkin 《Chembiochem : a European journal of chemical biology》2023,24(16):e202300313
Aryl diazonium cations are versatile bioconjugation reagents due to their reactivity towards electron-rich aryl residues and secondary amines, but historically their usage has been hampered by both their short lifespan in aqueous solution and the harsh conditions required to generate them in situ. Triazabutadienes address many of these issues as they are stable enough to endure multiple-step chemical syntheses and can persist for several hours in aqueous solution, yet upon UV-exposure rapidly release aryl diazonium cations under biologically-relevant conditions. This paper describes the synthesis of a novel maleimide-functionalized triazabutadiene suitable for site-selectively installing aryl diazonium cations into proteins at neutral pH; we show reaction with this molecule and a surface-cysteine of a thiol disulfide oxidoreductase. Through photoactivation of the site-selectively installed triazabutadiene motifs, we generate aryl diazonium functionality, which we further derivatize via azo-bond formation to electron-rich aryl species, showcasing the potential utility of this strategy for the generation of photoswitches or protein-drug conjugates. 相似文献
255.
Mieow Kee Chan Prasilla Kumaran Xavier Vigneswaran Thomas Eva Natasha Yi Shen Tee Alijah Mohd Aris Yoke Ping Ho Bee Chin Khor 《加拿大化工杂志》2023,101(7):3751-3758
Bimetallic nanoparticles have been widely studied for wastewater treatment, but the study of nanoFeCu for sewage treatment is minimal. In the previous work, ammonia was removed by nanoFeCu via an oxidation reaction, and nitrogen gas was released. However, the performance and reusability of nanoFeCu in treating industrial wastewater have not been reported elsewhere. This study revealed the performance of nanoFeCu for sewage treatment on both laboratory-scale and pilot-scale for the first time. A varied mass of embedded nanoFeCu (eFeCu4) was exposed to sewage water, and the quality of the effluent was measured in terms of ammonia, biological oxygen demand (BOD), and chemical oxygen demand (COD) removal. Fe2+ and Cu2+ concentrations were measured to determine the stability of eFeCu4 in nine reuse cycles. Results showed that the laboratory-scale experiment removed 20%–30% ammonia from sewage. A similar removal rate was reported in all nine cycles of reuse, which confirmed the usability and reliability of eFeCu4. In the pilot-scale study, ammonia was removed from ~22.3 to ~4.8 mg/L, while BOD and COD were reduced from ~204 to ~56 mg/L and ~71 to ~39.7 mg/L, respectively. The treated effluent quality complies with the effluent discharge standard of Malaysia, and it is also comparable with the effluent quality at sewage treatment plants in Malaysia and overseas. In conclusion, nanoFeCu could be an alternative method for sewage treatment due to its stability and pollutant removal performance. A sustainability and cost-effectiveness study should be conducted to determine the feasibility of a full-scale application. 相似文献