全文获取类型
收费全文 | 18171篇 |
免费 | 2151篇 |
国内免费 | 1231篇 |
专业分类
电工技术 | 2153篇 |
技术理论 | 3篇 |
综合类 | 2092篇 |
化学工业 | 545篇 |
金属工艺 | 294篇 |
机械仪表 | 2444篇 |
建筑科学 | 985篇 |
矿业工程 | 504篇 |
能源动力 | 209篇 |
轻工业 | 387篇 |
水利工程 | 337篇 |
石油天然气 | 214篇 |
武器工业 | 313篇 |
无线电 | 2098篇 |
一般工业技术 | 1616篇 |
冶金工业 | 591篇 |
原子能技术 | 111篇 |
自动化技术 | 6657篇 |
出版年
2024年 | 59篇 |
2023年 | 316篇 |
2022年 | 510篇 |
2021年 | 622篇 |
2020年 | 620篇 |
2019年 | 498篇 |
2018年 | 470篇 |
2017年 | 536篇 |
2016年 | 582篇 |
2015年 | 706篇 |
2014年 | 1164篇 |
2013年 | 995篇 |
2012年 | 1360篇 |
2011年 | 1516篇 |
2010年 | 1192篇 |
2009年 | 1279篇 |
2008年 | 1276篇 |
2007年 | 1449篇 |
2006年 | 1227篇 |
2005年 | 1157篇 |
2004年 | 964篇 |
2003年 | 766篇 |
2002年 | 645篇 |
2001年 | 537篇 |
2000年 | 369篇 |
1999年 | 212篇 |
1998年 | 123篇 |
1997年 | 85篇 |
1996年 | 63篇 |
1995年 | 63篇 |
1994年 | 36篇 |
1993年 | 24篇 |
1992年 | 16篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 7篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 6篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1964年 | 3篇 |
1963年 | 3篇 |
1961年 | 4篇 |
1960年 | 3篇 |
1958年 | 4篇 |
1957年 | 6篇 |
1956年 | 5篇 |
1955年 | 3篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
Shraddha Parate Vikas Kumar Danishuddin Jong Chan Hong Keun Woo Lee 《International journal of molecular sciences》2021,22(10)
Heparanase (Hpse) is an endo-β-D-glucuronidase capable of cleaving heparan sulfate side chains. Its upregulated expression is implicated in tumor growth, metastasis and angiogenesis, thus making it an attractive target in cancer therapeutics. Currently, a few small molecule inhibitors have been reported to inhibit Hpse, with promising oral administration and pharmacokinetic (PK) properties. In the present study, a ligand-based pharmacophore model was generated from a dataset of well-known active small molecule Hpse inhibitors which were observed to display favorable PK properties. The compounds from the InterBioScreen database of natural (69,034) and synthetic (195,469) molecules were first filtered for their drug-likeness and the pharmacophore model was used to screen the drug-like database. The compounds acquired from screening were subjected to molecular docking with Heparanase, where two molecules used in pharmacophore generation were used as reference. From the docking analysis, 33 compounds displayed higher docking scores than the reference and favorable interactions with the catalytic residues. Complex interactions were further evaluated by molecular dynamics simulations to assess their stability over a period of 50 ns. Furthermore, the binding free energies of the 33 compounds revealed 2 natural and 2 synthetic compounds, with better binding affinities than reference molecules, and were, therefore, deemed as hits. The hit compounds presented from this in silico investigation could act as potent Heparanase inhibitors and further serve as lead scaffolds to develop compounds targeting Heparanase upregulation in cancer. 相似文献
2.
目的 为了更科学地研究和检验可穿戴产品的适合性,提出一种适合性检验方法,能够精确保留现实环境中的产品佩戴关系,并能将现实与虚拟的适合性检验研究相结合,得到合理的适合性检验结果.方法 以虚拟现实眼镜的适合性检验为例,通过高精度的三维测量技术将现实环境中的人、产品以及人—产品佩戴关系转化为三维虚拟信息,并以人—产品佩戴三维模型为参考基准对齐人和产品的虚拟模型,得到保留现实佩戴关系的人—产品佩戴模型组,再应用偏差分析法得出人—机佩戴区域的可视化适合性结果和统计数据,结合主观评价方法进一步分析产品的适合性.结论 虚实结合的产品适合性检验方法可在虚拟环境中高精度地保留现实环境中的人—产品佩戴关系,并能得到可视化的适合性检验结果,为检验和指导产品的适合性提供依据. 相似文献
3.
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
4.
5.
6.
Navid Khaleghimoghaddam Havva Alkan Bala G zin zmen &Scedil erefnur zt rk 《建筑学研究前沿(英文版)》2022,11(5):877-890
Environment psychologically affects individuals. According to the base of cognitive psychology, there is a direct relationship between human behavior, environment, and emotional process. Assuming that pleasantness and unpleasantness are associated with peripheral nervous system activation, the current study aims to explore if the pleasant or unpleasant architectural places can stimulate the brain regions engaged in emotions or not. As the main contribution, we used functional magnetic resonance imaging (fMRI) measuring blood oxygenation level-dependent (BOLD) changes to effectively detect the brain's region that mainly responds to the emotional-perceptual processes. Based on the results of examining the emotional assessment model of “Pleasure-Arousal” applied to 140 students, 30 most-rated images representing 15 pleasant and 15 unpleasant places were shown to 32 participants in a 1.5-T MRI scanner. After applying standard preprocessing steps (re-alignment, slice-timing, co-registration, segmentation, normalization, and smoothing) to functional MR images, first-level analysis was applied to each subject. The results were evaluated using statistical corrections at different levels for female and male participants with the second-level analysis. In conclusion, it has been shown that there is a significant linkage between environmental experience and brain activation so that the architectural qualities can change blood flow in specific brain regions. 相似文献
7.
为解释道床与盾构隧道管片产生脱空的现象,研究新混凝土在浇筑后由干燥收缩产生的裂缝机理。基于虚拟元推导任意多边形骨料的刚度矩阵格式,利用UEL子程序实现有限元与虚拟元的耦合计算,纯弯梁数值试验结果表明耦合法较有限元法计算效率明显提升,且具有较好的稳定性。在此基础上,建立细观尺度下新老混凝土的干缩数值模型,并通过圆盘干缩模型验证了模型参数。研究骨料和砂浆的应力分布、内部湿度与裂缝发展的对应关系以及新老混凝土表面和界面的应力发展。结果表明:①收缩过程中,骨料主要承受压应力作用,砂浆沿骨料边界的切线方向受骨料约束作用易形成收缩裂缝,在新混凝土表面首先出现大量微小裂缝,随后界面两端发生剥离; ②受表面下骨料的约束作用,新混凝土表面拉应力呈现“驼峰”分布。开裂后表面被划分为多个收缩区,收缩区边界受拉应力,内部受压应力;③界面的拉伸和剪切应力由两侧开始增加,并且随着界面剥离的增加不断内移。在界面内部未剥离区域内存在由界面附近骨料约束导致的局部压应力和剪切应力增大。 相似文献
8.
总结一次野外重大活动饮食卫生保障的针对性做法和经验,为以后遂行多样化任务提供参考。从食谱审查、从业人员卫生管理及培训、采购保管、加工制作、餐饮具消毒以及留样备检等环节严格把关,强化常态食品卫生监督;科学分析餐饮环节容易导致疫情传播的风险点,从人、物、环境和预案4个方面开展督导;针对野外食品加工及人员大规模长时间野外就餐,指导餐饮单元选址开设、做好环境卫生管理、保障加工用水及食材安全、保障运输前送环节的食品安全及人员就餐过程卫生、指导智能化餐厨设备使用。提高餐饮单位负责人及从业人员的食品安全意识;提高保障人员的卫生法律素质和专业技术能力,关注新的风险点。加强保障人员自身管理及从业人员的卫生管理,树立良好形象。 相似文献
9.
10.
针对CAGAN(Conditional Analogy GAN)换衣后效果模糊,在目标衣服与原始衣服长短不一致时效果一般,相对目标衣服保留过少的细节等问题做了相关研究并对CAGAN进行了改进,提出了新的虚拟试衣方式。经过改进的CAGAN生成一个粗糙的结果,由该结果得到目标衣服穿在模特身上改变形状后的mask,接下来利用mask对目标衣服进行变形,综合变形的衣服和第一步的结果便得到最终的试衣图像。实验结果表明,该方法解决了前面存在的问题,而且取得了非常好的效果。 相似文献