全文获取类型
收费全文 | 2942篇 |
免费 | 253篇 |
国内免费 | 88篇 |
专业分类
电工技术 | 99篇 |
综合类 | 88篇 |
化学工业 | 801篇 |
金属工艺 | 134篇 |
机械仪表 | 133篇 |
建筑科学 | 139篇 |
矿业工程 | 35篇 |
能源动力 | 185篇 |
轻工业 | 343篇 |
水利工程 | 43篇 |
石油天然气 | 64篇 |
武器工业 | 12篇 |
无线电 | 291篇 |
一般工业技术 | 426篇 |
冶金工业 | 73篇 |
原子能技术 | 14篇 |
自动化技术 | 403篇 |
出版年
2024年 | 13篇 |
2023年 | 55篇 |
2022年 | 134篇 |
2021年 | 188篇 |
2020年 | 140篇 |
2019年 | 140篇 |
2018年 | 171篇 |
2017年 | 161篇 |
2016年 | 174篇 |
2015年 | 156篇 |
2014年 | 202篇 |
2013年 | 280篇 |
2012年 | 263篇 |
2011年 | 237篇 |
2010年 | 179篇 |
2009年 | 129篇 |
2008年 | 83篇 |
2007年 | 91篇 |
2006年 | 70篇 |
2005年 | 82篇 |
2004年 | 55篇 |
2003年 | 42篇 |
2002年 | 36篇 |
2001年 | 45篇 |
2000年 | 42篇 |
1999年 | 17篇 |
1998年 | 27篇 |
1997年 | 6篇 |
1996年 | 10篇 |
1995年 | 14篇 |
1994年 | 13篇 |
1993年 | 5篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 6篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有3283条查询结果,搜索用时 31 毫秒
11.
On the basis of a geological - volcanological - geophysical survey, integrated with petrological and geochronological data, a structural model, including a shallow magmatic body, was defined for the Ribeira Grande area, Sao Miguel island (Azores). Two series of production tests were carried out in the Pico Vermelho 1 and Ribeira Grande 1 wells, which led to a preliminary definition of the deep fluid circulation. The data obtained from these studies were used to reconstruct a preliminary model of the Ribeira Grande geothermal field. 相似文献
12.
Kolivand Hoshang Joudaki Saba Sunar Mohd Shahrizal Tully David 《Neural computing & applications》2021,33(10):4945-4963
Neural Computing and Applications - Hand pose tracking is essential in sign languages. An automatic recognition of performed hand signs facilitates a number of applications, especially for people... 相似文献
13.
Izzuddin Tarmizi Ahmad Safri Norlaili Mat Othman Mohd Afzan 《Neural computing & applications》2021,33(11):6233-6246
Neural Computing and Applications - This paper introduces the use of the one-dimensional convolutional neural network (1D-CNN) for end-to-end EEG decoding with application towards a BCI system with... 相似文献
14.
光纤陀螺姿态测量系统中的信号采集和处理是系统的一个重要环节;文章介绍了基于FPGA的光纤陀螺信号采集处理卡的设计过程,采用Verilog HDL实现FPGA内部逻辑电路设计,选用AD7846完成信号的数模转换,通过FPGA编程实现光纤陀螺的标定和误差补偿,设计了RS232/422通用异步串口通信硬件电路并在FPGA上实现了串口通信;实验结果表明:该卡能够准确实时地采集并按预定的设计处理光纤陀螺信号。 相似文献
15.
Mohd Akram Hira Lal Mohammad Osama Farah Ansari Sana Anwar Kabir-ud-Din Ajaz Ahmad Samreen Naved Azum Hadi M. Marwani Abdullah M. Asiri 《Journal of surfactants and detergents》2021,24(1):35-49
In this study, we prepared a novel series of diester-functionalized cationic gemini surfactants (Cm-E2O2-Cm) containing ethylene oxide as a spacer with varying alkyl chain lengths and characterized by 1H NMR, FT-IR, elemental analysis, and ESI-MS. The physicochemical properties of the geminis were explored by tensiometry, fluorescence, dye solubilization, and Krafft point. These geminis acquire superior surface activity than the conventional surfactants. Fluorescence spectroscopy analysis affirmed that the micropolarity and aggregation number of micelles diminished with increase in the alkyl chain length. These geminis represent a new group of amphiphiles of considerably high biodegradability, better cleavability, and low toxicity as assessed by BOD test, FT-IR analysis, and HC50 analysis, respectively. They also showed significant level of antimicrobial activity toward some specified bacterial strains of Gram-positive and Gram-negative by using agar well diffusion method. Furthermore, the thermogravimetric analysis provided information regarding thermal stabilities of the newly synthesized gemini surfactants. 相似文献
16.
Mohd N. Mat Nor Ilva D. Rupenthal Colin R. Green Monica L. Acosta 《International journal of molecular sciences》2021,22(4)
Dysregulation of retinal function in the early stages of light-induced retinal degeneration involves pannexins and connexins. These two types of proteins may contribute to channels that release ATP, leading to activation of the inflammasome pathway, spread of inflammation and retinal dysfunction. However, the effect of pannexin channel block alone or block of both pannexin channels and connexin hemichannels in parallel on retinal activity in vivo is unknown. In this study, the pannexin channel blocker probenecid and the connexin hemichannel blocker tonabersat were used in the light-damaged rat retina. Retinal function was evaluated using electroretinography (ERG), retinal structure was analyzed using optical coherence tomography (OCT) imaging and the tissue response to light-induced injury was assessed immunohistochemically with antibodies against glial fibrillary acidic protein (GFAP), Ionized calcium binding adaptor molecule 1 (Iba-1) and Connexin43 (Cx43). Probenecid did not further enhance the therapeutic effect of connexin hemichannel block in this model, but on its own improved activity of certain inner retina neurons. The therapeutic benefit of blocking connexin hemichannels was further evaluated by comparing these data against results from our previously published studies that also used the light-damaged rat retina model. The analysis showed that treatment with tonabersat alone was better than probenecid alone at restoring retinal function in the light-damaged retina model. The results assist in the interpretation of the differential action of connexin hemichannel and pannexin channel therapeutics for potential treatment of retinal diseases. 相似文献
17.
18.
Shaikh Mohd Rizwan Uddin Loan Sajad A. Alharbi Abdullah G. 《Journal of Computational Electronics》2021,20(6):2360-2368
Journal of Computational Electronics - In this work, a Schottky junction on the drain side employing low workfunction (WF) metal is proposed as a method to suppress the OFF-state leakage in... 相似文献
19.
Fatin N. Mohd Jaya Sergio G. Garcia Francesc E. Borras Dolores Guerrero Godfrey C. F. Chan Marcella Franquesa 《International journal of molecular sciences》2021,22(9)
Regulatory B (Breg) cells are endowed with immune suppressive functions. Various human and murine Breg subtypes have been reported. While interleukin (IL)-10 intracellular staining remains the most reliable way to identify Breg cells, this technique hinders further essential functional studies. Recent findings suggest that CD9 is an effective surface marker of murine IL-10 competent Breg cells. However, the stability of CD9 and its relevance as a unique marker for human Breg cells, which have been widely characterized as CD24hiCD38hi, have not been investigated. Here, we demonstrate that CD9 expression is sensitive to in vitro B cell stimulations. CD9 expression could either be re-expressed or downregulated in purified CD9-negative B cells and CD9-positive B cells, respectively. We found no significant differences in the Breg differentiation capacity of the CD9-negative and CD9-positive B cells. Furthermore, CD9-positive B cells co-express CD40 and CD86, suggesting their nature as B cell activation or co-stimulatory molecules, rather than regulatory ones. Therefore, we report the relatively unstable CD9 as a distinct surface molecule, indicating the need for further research for a more reliable marker to purify human Breg cells. 相似文献
20.
隔膜作为锂离子电池的重要组成部分,用于阻隔阴极和阳极直接接触,同时为锂离子在电极间的传输提供有效通道。聚酰亚胺隔膜因其具有充放电循环寿命长、机械强度适中、良好的电绝缘性能以及自熄能力等优点,而受到广泛关注。以对苯二甲胺作为交联剂,将聚酰亚胺隔膜进行化学交联,研究了交联时间与隔膜形貌、结构及性能之间的构效关系。随着交联时间的增加,隔膜的孔隙率和吸液率逐渐降低,电解液接触角和机械强度逐渐增大。电化学测试表明,随着交联时间的增加,隔膜的本体阻抗逐渐增大,进而离子电导率逐渐降低,而交联隔膜的界面阻抗均远小于未交联隔膜,且交联隔膜的电化学窗口也均大于未交联隔膜。通过组装半电池测试发现,交联隔膜所组装电池的倍率性能和循环性能均优于未交联隔膜,当交联时间为48 h时,电池性能表现最优,循环100次以后,放电比容量为130.2 mA·h/g,容量保留率为91.1%。 相似文献