全文获取类型
收费全文 | 1806篇 |
免费 | 106篇 |
国内免费 | 13篇 |
专业分类
电工技术 | 24篇 |
综合类 | 11篇 |
化学工业 | 490篇 |
金属工艺 | 49篇 |
机械仪表 | 106篇 |
建筑科学 | 47篇 |
矿业工程 | 11篇 |
能源动力 | 56篇 |
轻工业 | 157篇 |
水利工程 | 8篇 |
石油天然气 | 15篇 |
无线电 | 236篇 |
一般工业技术 | 310篇 |
冶金工业 | 160篇 |
原子能技术 | 21篇 |
自动化技术 | 224篇 |
出版年
2023年 | 20篇 |
2022年 | 59篇 |
2021年 | 125篇 |
2020年 | 45篇 |
2019年 | 46篇 |
2018年 | 59篇 |
2017年 | 52篇 |
2016年 | 53篇 |
2015年 | 40篇 |
2014年 | 70篇 |
2013年 | 136篇 |
2012年 | 90篇 |
2011年 | 109篇 |
2010年 | 84篇 |
2009年 | 99篇 |
2008年 | 86篇 |
2007年 | 81篇 |
2006年 | 57篇 |
2005年 | 65篇 |
2004年 | 49篇 |
2003年 | 42篇 |
2002年 | 48篇 |
2001年 | 27篇 |
2000年 | 27篇 |
1999年 | 26篇 |
1998年 | 50篇 |
1997年 | 51篇 |
1996年 | 36篇 |
1995年 | 24篇 |
1994年 | 22篇 |
1993年 | 19篇 |
1992年 | 3篇 |
1991年 | 11篇 |
1990年 | 4篇 |
1989年 | 10篇 |
1988年 | 17篇 |
1987年 | 4篇 |
1986年 | 3篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 4篇 |
1978年 | 7篇 |
1977年 | 5篇 |
1975年 | 3篇 |
1974年 | 3篇 |
1973年 | 8篇 |
排序方式: 共有1925条查询结果,搜索用时 187 毫秒
61.
Andrej Lotrič Mihael Sekavčnik Igor Kuštrin Mitja Mori 《International Journal of Hydrogen Energy》2021,46(16):10143-10160
We present the results of a life-cycle assessment (LCA) for the manufacturing and end-of-life (EoL) phases of the following fuel-cell and hydrogen (FCH) technologies: alkaline water electrolyser (AWE), polymer-electrolyte-membrane water electrolyser (PEMWE), high-temperature (HT) and low-temperature (LT) polymer-electrolyte-membrane fuel cells (PEMFCs), together with the balance-of-plant components. New life-cycle inventories (LCIs), i.e., material inputs for the AWE, PEMWE and HT PEMFC are developed, whereas the existing LCI for the LT PEMFC is adopted from a previous EU-funded project. The LCA models for all four FCH technologies are created by modelling the manufacturing phase, followed by defining the EoL strategies and processes used and finally by assessing the effects of the EoL approach using environmental indicators. The effects are analysed with a stepwise approach, where the CML2001 assessment method is used to evaluate the environmental impacts. The results show that the environmental impacts of the manufacturing phase can be substantially reduced by using the proposed EoL strategies (i.e., recycled materials being used in the manufacturing phase and replacing some of the virgin materials). To point out the importance of critical materials (in this case, the platinum-group metals or PGMs) and their recycling strategies, further analyses were made. By comparing the EoL phase with and without the recycling of PGMs, an increase in the environmental impacts is observed, which is much greater in the case of both fuel-cell systems, because they contain a larger quantity of PGMs. 相似文献
62.
63.
The Asteraceae family is one of the largest flowering plant families, with over 1600 genera and 2500 species worldwide. Some of its most well-known taxa are lettuce, chicory, artichoke, daisy and dandelion. The members of the Asteraceae have been used in the diet and for medicine for centuries. Despite their wide diversity, most family members share a similar chemical composition: for example, all species are good sources of inulin, a natural polysaccharide with strong prebiotic properties. They also demonstrate strong antioxidant, anti-inflammatory and antimicrobial activity, as well as diuretic and wound healing properties. Their pharmacological effects can be attributed to their range of phytochemical compounds, including polyphenols, phenolic acids, flavonoids, acetylenes and triterpenes. One such example is arctiin: a ligand with numerous antioxidant, antiproliferative and desmutagenic activities. The family is also a source of sesquiterpene lactones: the secondary metabolites responsible for the bitter taste of many plants. This mini review examines the current state of literature regarding the positive effect of the Asteraceae family on human health. 相似文献
64.
Remediation of diesel‐contaminated soil using in situ chemical oxidation (ISCO) and the effects of common oxidants on the indigenous microbial community: a comparison study
下载免费PDF全文
![点击此处可从《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
65.
Sonia R. Merritt Agata A. Exner Zhenghong Lee Horst A. von Recum 《Advanced Engineering Materials》2012,14(5):B266-B278
Polymer processing via electrospinning is a cost effective and scalable method for preparing nanofibers with industrial, electrical, and biomedical applications, particularly tissue engineering and drug delivery. Characterization methods for these fibers include microscopy techniques for vitro surface morphology information, spectroscopy methods to determine in vitro chemical composition, and medical imaging tools for in vivo assessment of morphology and efficacy of implanted material. The focus of this paper is be on recent applications for electrospun nanofibers, in vitro characterization methods, and medical imaging modalities that can be used for in vivo assessment of the fibers, as well as insights in how to adapt existing techniques toward the characterization of electrospun materials. 相似文献
66.
Park Ji-Woo Ku Tae-Wan Kim Jeong Kim Kwang-Ho Kang Beom-Soo 《Journal of Mechanical Science and Technology》2016,30(5):2203-2210
Journal of Mechanical Science and Technology - Flexible forming technology such as Multi-point dieless forming (MDF) has benefits for the sheet metal field because it can implement a variety of... 相似文献
67.
68.
The antioxidant activities and nutritional properties of Jeonyak made with beef bone stock and gelatin were investigated. Traditional Jeonyak (J1) was prepared with beef bone stock, whereas modified Jeonyak was made with gelatin and honey (J2) or with gelatin and oligosaccharides (J3). All 3 kinds of Jeonyak had antioxidant activities and J1 had the highest activity. The α-glucosidase inhibitory activity was measured to investigate the antidiabetic effect and J3 had the highest inhibitory activity of 80.47%. Glycine was the most abundant amino acid in all 3 kinds of Jeonyak. Both traditional and modified Jeonyaks have antioxidative and antidiabetic effects, suggesting that Jeonyak can be used as an effective traditional functional food. 相似文献
69.
70.
H. Ku F. Cardona D. Rogers J.-C. Munoz 《Journal of Materials Engineering and Performance》2010,19(6):912-919
Epoxy resin was mixed with phenolic resins in different percentages by weight. Composite 40/60 means the proportion by weight
of epoxy resin is 40%. It was found that only composites 50/50 and 40/60 could be cured in ambient conditions. Dynamic mechanical
analysis showed that only these two composites form interpenetrating polymer network. The addition of linseed oil to the two
resins results also in the formation of interpenetrating network irrespective of proportion by weight of the resins; the mechanical
properties will only be better when the percentage by weight of epoxy resin is higher; the aim of reducing cost and at the
same time maintaining the mechanical properties cannot be fully achieved because epoxy resin is much more expensive than its
counterpart. 相似文献