全文获取类型
收费全文 | 161372篇 |
免费 | 17406篇 |
国内免费 | 10836篇 |
专业分类
电工技术 | 13320篇 |
技术理论 | 6篇 |
综合类 | 13383篇 |
化学工业 | 22589篇 |
金属工艺 | 10070篇 |
机械仪表 | 11294篇 |
建筑科学 | 13407篇 |
矿业工程 | 5541篇 |
能源动力 | 4816篇 |
轻工业 | 11644篇 |
水利工程 | 4136篇 |
石油天然气 | 7748篇 |
武器工业 | 2243篇 |
无线电 | 19674篇 |
一般工业技术 | 16209篇 |
冶金工业 | 6456篇 |
原子能技术 | 2343篇 |
自动化技术 | 24735篇 |
出版年
2024年 | 800篇 |
2023年 | 2391篇 |
2022年 | 4999篇 |
2021年 | 7078篇 |
2020年 | 5209篇 |
2019年 | 4171篇 |
2018年 | 4580篇 |
2017年 | 5316篇 |
2016年 | 4871篇 |
2015年 | 7205篇 |
2014年 | 8990篇 |
2013年 | 10454篇 |
2012年 | 12510篇 |
2011年 | 13470篇 |
2010年 | 12474篇 |
2009年 | 11934篇 |
2008年 | 11869篇 |
2007年 | 11140篇 |
2006年 | 10376篇 |
2005年 | 8440篇 |
2004年 | 6006篇 |
2003年 | 4593篇 |
2002年 | 4415篇 |
2001年 | 3754篇 |
2000年 | 3105篇 |
1999年 | 2314篇 |
1998年 | 1362篇 |
1997年 | 1183篇 |
1996年 | 1014篇 |
1995年 | 861篇 |
1994年 | 628篇 |
1993年 | 493篇 |
1992年 | 381篇 |
1991年 | 262篇 |
1990年 | 211篇 |
1989年 | 174篇 |
1988年 | 120篇 |
1987年 | 93篇 |
1986年 | 89篇 |
1985年 | 34篇 |
1984年 | 31篇 |
1983年 | 35篇 |
1982年 | 30篇 |
1981年 | 32篇 |
1980年 | 30篇 |
1979年 | 12篇 |
1978年 | 7篇 |
1977年 | 9篇 |
1959年 | 26篇 |
1951年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
针对目前集成电路版图分析与设计课程存在教学方法老化、教学模式形式化等问题,本文以OBE-CDIO教育理念为指导,对”集成电路版图分析与设计”课程的课程教学模式、课程设计、项目式教学方式和课程考核方式等方面的改革进行有益的探索与实践。将工程教学认证中对学生的专业毕业要求作为制定教学目标的依据,将BB网络平台、ISO9001等现代化教学资源和质量标准融入课堂教学,采用OBE-CDIO能力教学理念指导课程设计,实现教学环节与考核环节的科学化与多元化,通过引入课程思政激发学生学习热情,树立社会主义核心价值观,全面地培养学生的综合版图分析与设计能力和素养。 相似文献
22.
Wenjie Liu Jianmin Liu Shu Xing Xiaobin Li Liwen Han Kechun Liu Tao Wei Mingyang Zhou 《European Journal of Lipid Science and Technology》2021,123(6):2000276
In this study, the anti-atherosclerotic properties of three marine phospholipids (MPLs) extracts from fishery by-products including codfish roe, squid gonad, and shrimp head are verified. Their effects on key factors involved in atherosclerosis are examined and compared to explore whether the differences in their constitutions lead to the differences in the function. All three MPLs dampen oxidation of low- density lipoproteins (LDL) in vitro. Treating RAW264.7 macrophages and HUVECs endothelial cells with each MPLs ranging 10–100 µg mL−1 does not decrease cell viability, yet ox-LDL caused cytotoxicity of both cells are alleviated by 50 or 100 µg mL−1 MPLs treatment. In addition, the three MPLs reduce ox-LDL induced macrophage foam-like transition, mainly through inhibition of lipid uptake. Of the three MPLs, the one from squid gonad exhibits the best effect. On the other hand, all three MPLs modulate inflammatory responses, equally, by inhibiting the adhesion of monocytes to endothelial cells, and decreasing secretion of pro-inflammatory cytokines IL-6 and MCP-1. Using a high-cholesterol diet induced zebrafish model, it is found that all three MPLs, especially the one from squid gonad, alleviates cholesterol accumulation in early plaques, and decreases total cholesterol as well as lipid peroxide in vivo. Practical Applications: As a way of making the best of the increasingly scarce marine resources, valuable lipid components can be recovered from by-products and wastes from the fishery industry. Here, we tested the anti-atherosclerotic effects and the mechanisms of three MPLs extracted from codfish roe, squid gonad, and shrimp head. Our study provides further evidence that marine phospholipids extracted from fishery by-products could protect against atherosclerosis, and helps to elucidate the structure-function relationship of MPLs. 相似文献
23.
24.
Jun Dong Cho Luis Cavazos Quero Jorge Iranzo Bartolom Do Won Lee Uran Oh Inae Lee 《Color research and application》2021,46(1):103-116
A recent development in tactile technology enables an improvement in the appreciation of the visual arts for people with visual impairment (PVI). The tactile sense, in conjunction with, or a possibly as an alternative to, the auditory sense, would allow PVIs to approach artwork in a more self‐driven and engaging way that would be difficult to achieve with just an auditory stimulus. Tactile colour pictograms (TCPs), which are raised geometric patterns, are ideographic characters that are designed to enable PVIs to identify colours and interpret information by touch. In this article, three TCPs are introduced to code colours in the Munsell colour system. Each colour pattern consists of a basic cell size of 10 mm × 10 mm to represent the patterns consistently in terms of regular shape. Each TCP consists of basic geometric patterns that are combined to create primary, secondary, and tertiary colour pictograms of shapes indicating colour hue, intensity and lightness. Each TCP represents 29 colours including six hues; they were then further expanded to represent 53 colours. Two of them did not increase the cell size, the other increased the cell size 1.5 times for some colours, such as yellow‐orange, yellow, blue, and blue‐purple. Our proposed TCPs use a slightly larger cell size compared to most tactile patterns currently used to indicate colour, but code for more colours. With user experience and identification tests, conducted with 23 visually impaired adults, the effectiveness of the TCPs suggests that they were helpful for the participants. 相似文献
25.
26.
Wei Shaowei Yu Guoxian Wang Jun Domeniconi Carlotta Zhang Xiangliang 《Machine Learning》2021,110(6):1505-1526
Machine Learning - Traditional clustering algorithms focus on a single clustering result; as such, they cannot explore potential diverse patterns of complex real world data. To deal with this... 相似文献
27.
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are... 相似文献
28.
29.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018)
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
30.