全文获取类型
收费全文 | 35123篇 |
免费 | 3276篇 |
国内免费 | 1450篇 |
专业分类
电工技术 | 2672篇 |
技术理论 | 6篇 |
综合类 | 3763篇 |
化学工业 | 3138篇 |
金属工艺 | 1184篇 |
机械仪表 | 4829篇 |
建筑科学 | 4840篇 |
矿业工程 | 1739篇 |
能源动力 | 1689篇 |
轻工业 | 1101篇 |
水利工程 | 1673篇 |
石油天然气 | 962篇 |
武器工业 | 472篇 |
无线电 | 1251篇 |
一般工业技术 | 7022篇 |
冶金工业 | 1308篇 |
原子能技术 | 256篇 |
自动化技术 | 1944篇 |
出版年
2024年 | 144篇 |
2023年 | 454篇 |
2022年 | 1034篇 |
2021年 | 1082篇 |
2020年 | 1179篇 |
2019年 | 827篇 |
2018年 | 831篇 |
2017年 | 1059篇 |
2016年 | 1173篇 |
2015年 | 1195篇 |
2014年 | 2231篇 |
2013年 | 2019篇 |
2012年 | 2659篇 |
2011年 | 2696篇 |
2010年 | 2053篇 |
2009年 | 2015篇 |
2008年 | 1727篇 |
2007年 | 2449篇 |
2006年 | 2186篇 |
2005年 | 1764篇 |
2004年 | 1459篇 |
2003年 | 1319篇 |
2002年 | 1047篇 |
2001年 | 971篇 |
2000年 | 848篇 |
1999年 | 665篇 |
1998年 | 489篇 |
1997年 | 457篇 |
1996年 | 343篇 |
1995年 | 298篇 |
1994年 | 258篇 |
1993年 | 165篇 |
1992年 | 152篇 |
1991年 | 127篇 |
1990年 | 97篇 |
1989年 | 115篇 |
1988年 | 80篇 |
1987年 | 43篇 |
1986年 | 21篇 |
1985年 | 17篇 |
1984年 | 13篇 |
1983年 | 16篇 |
1982年 | 25篇 |
1981年 | 5篇 |
1980年 | 4篇 |
1979年 | 7篇 |
1965年 | 5篇 |
1964年 | 3篇 |
1961年 | 3篇 |
1959年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
2.
Raquel Cano Jos L. Prez Liss Angarita Dvila ngel Ortega Yosselin Gmez Nereida Josefina Valero-Cedeo Heliana Parra Alexander Manzano Teresa Isabel Vliz Castro María P. Díaz Albornoz Gabriel Cano Joselyn Rojas-Quintero Maricarmen Chacín Valmore Bermúdez 《International journal of molecular sciences》2021,22(9)
Non-alcoholic fatty liver disease (NAFLD) is considered the most common liver disorder, affecting around 25% of the population worldwide. It is a complex disease spectrum, closely linked with other conditions such as obesity, insulin resistance, type 2 diabetes mellitus, and metabolic syndrome, which may increase liver-related mortality. In light of this, numerous efforts have been carried out in recent years in order to clarify its pathogenesis and create new prevention strategies. Currently, the essential role of environmental pollutants in NAFLD development is recognized. Particularly, endocrine-disrupting chemicals (EDCs) have a notable influence. EDCs can be classified as natural (phytoestrogens, genistein, and coumestrol) or synthetic, and the latter ones can be further subdivided into industrial (dioxins, polychlorinated biphenyls, and alkylphenols), agricultural (pesticides, insecticides, herbicides, and fungicides), residential (phthalates, polybrominated biphenyls, and bisphenol A), and pharmaceutical (parabens). Several experimental models have proposed a mechanism involving this group of substances with the disruption of hepatic metabolism, which promotes NAFLD. These include an imbalance between lipid influx/efflux in the liver, mitochondrial dysfunction, liver inflammation, and epigenetic reprogramming. It can be concluded that exposure to EDCs might play a crucial role in NAFLD initiation and evolution. However, further investigations supporting these effects in humans are required. 相似文献
3.
4.
Karolina Storesund Francine Amon Anne Steen‐Hansen Shayesteh Haghighatpanah Ida Larsson 《火与材料》2021,45(1):181-190
The aim of this exploratory study has been to investigate the fire properties and environmental aspects of different upholstery material combinations, mainly for domestic applications. An analysis of the sustainability and circularity of selected textiles, along with lifecycle assessment, is used to qualitatively evaluate materials from an environmental perspective. The cone calorimeter was the primary tool used to screen 20 different material combinations from a fire performance perspective. It was found that textile covers of conventional fibres such as wool, cotton and polyester, can be improved by blending them with fire resistant speciality fibres. A new three‐dimensional web structure has been examined as an alternative padding material, showing preliminary promising fire properties with regard to ignition time, heat release rates and smoke production. 相似文献
5.
6.
伏彩萍 《有色金属(冶炼部分)》2020,(6):66-69
针对现有柠檬酸铋制备工艺合成时间长、能耗高、产品纯度不高等不足,介绍了一种常温下制备柠檬酸铋的新工艺。新工艺制备时间短,制备的柠檬酸铋产品质量好,合成过程产生的废水可循环利用,废气经碱液循环吸收可生产硝酸钠副产品。 相似文献
7.
A small handful of recent studies have addressed a phenomenon known as “phantom vibration syndrome”. This refers to when phone users perceive their device to vibrate, indicating that a call or text is incoming, when in fact the phone did not vibrate at all. Though these studies show that most users do not find phantom vibration hallucinations to be very bothersome, they also find that a large majority of users experience this phenomenon. This paper explores what the striking prevalence of phantom vibration syndrome means for our contemporary relationships with technology. I begin with a review of the theories purporting to explain these data, which largely rely on particular understandings of the brain. Next I develop an alternative theory of phantom vibration syndrome based on insights from the philosophical tradition of phenomenology. This account considers the ways users develop bodily and perceptual habits regarding how the phone is understood and used. By critically contrasting these different theories, we can refine our questions about what the high prevalence of phantom vibration syndrome implies about our contemporary technological situation. 相似文献
8.
自工业革命以来人类社会的发展和经济的建设就离不开对矿产资源的使用。我国自改革开放以来,经济得到了前所未有的飞速发展,人民的生活水平日益提高,但经济高速发展的背后,存在着对矿产资源过度开采和使用的问题。矿产资源的不合理开采和使用对原有的自然环境造成了严重的破坏,为了改善此现状,对矿山地质环境的恢复治理技术的研究就至关重要。本文就矿山地质恢复治理的意义进行阐述,进一步对其方法进行探究,最终提出有关的措施和方法。 相似文献
9.
Niluka M. Dissanayake Kelley M. Current Sherine O. Obare 《International journal of molecular sciences》2015,16(10):23482-23516
In recent years, there has been an increased interest in the design and use of iron oxide materials with nanoscale dimensions for magnetic, catalytic, biomedical, and electronic applications. The increased manufacture and use of iron oxide nanoparticles (IONPs) in consumer products as well as industrial processes is expected to lead to the unintentional release of IONPs into the environment. The impact of IONPs on the environment and on biological species is not well understood but remains a concern due to the increased chemical reactivity of nanoparticles relative to their bulk counterparts. This review article describes the impact of IONPs on cellular genetic components. The mutagenic impact of IONPs may damage an organism’s ability to develop or reproduce. To date, there has been experimental evidence of IONPs having mutagenic interactions on human cell lines including lymphoblastoids, fibroblasts, microvascular endothelial cells, bone marrow cells, lung epithelial cells, alveolar type II like epithelial cells, bronchial fibroblasts, skin epithelial cells, hepatocytes, cerebral endothelial cells, fibrosarcoma cells, breast carcinoma cells, lung carcinoma cells, and cervix carcinoma cells. Other cell lines including the Chinese hamster ovary cells, mouse fibroblast cells, murine fibroblast cells, Mytilus galloprovincialis sperm cells, mice lung cells, murine alveolar macrophages, mice hepatic and renal tissue cells, and vero cells have also shown mutagenic effects upon exposure to IONPs. We further show the influence of IONPs on microorganisms in the presence and absence of dissolved organic carbon. The results shed light on the transformations IONPs undergo in the environment and the nature of the potential mutagenic impact on biological cells. 相似文献
10.
针对大型旋转机械通过临界转速时振动过大及运行中故障频发等问题,搭建转子试验台,模拟启停机过程和碰摩、不对中故障。不改变原有支撑形式,安装自主设计的磁流变阻尼器,在不停机的情况下,试验研究阻尼器抑制转子通过临界转速时振动过大及各类故障振动。试验结果表明,阻尼器可以有效抑制转子系统临界转速附近的振动,降幅在60%以上;转子发生碰摩或不对中故障时,阻尼器可以降低其高倍频振动。 相似文献