首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   122828篇
  免费   12415篇
  国内免费   7709篇
电工技术   9131篇
技术理论   3篇
综合类   9645篇
化学工业   18193篇
金属工艺   7440篇
机械仪表   8194篇
建筑科学   9525篇
矿业工程   3677篇
能源动力   4042篇
轻工业   8895篇
水利工程   2946篇
石油天然气   5239篇
武器工业   1384篇
无线电   15602篇
一般工业技术   13516篇
冶金工业   5650篇
原子能技术   1826篇
自动化技术   18044篇
  2024年   483篇
  2023年   1554篇
  2022年   3172篇
  2021年   4559篇
  2020年   3393篇
  2019年   2916篇
  2018年   3176篇
  2017年   3674篇
  2016年   3492篇
  2015年   5026篇
  2014年   6462篇
  2013年   7719篇
  2012年   8933篇
  2011年   9737篇
  2010年   9083篇
  2009年   8745篇
  2008年   8806篇
  2007年   8488篇
  2006年   7923篇
  2005年   6346篇
  2004年   4883篇
  2003年   4239篇
  2002年   4367篇
  2001年   3689篇
  2000年   2736篇
  1999年   1992篇
  1998年   1476篇
  1997年   1207篇
  1996年   945篇
  1995年   739篇
  1994年   554篇
  1993年   498篇
  1992年   320篇
  1991年   268篇
  1990年   208篇
  1989年   189篇
  1988年   131篇
  1987年   120篇
  1986年   119篇
  1985年   63篇
  1984年   54篇
  1983年   49篇
  1982年   36篇
  1981年   64篇
  1980年   41篇
  1979年   31篇
  1978年   31篇
  1977年   52篇
  1976年   47篇
  1959年   20篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
11.
Zhang  Qi  Wang  Yujing  Zhang  Xueling  Song  Jun  Li  Yinlei  Wu  Xuehong  Yuan  Kunjie 《Journal of Materials Science》2022,57(14):7208-7224
Journal of Materials Science - Form-stable composite phase change materials (C-PCMs) prepared by microencapsulation method and porous matrix adsorption method need for compression molding after...  相似文献   
12.
13.
To theoretically explore amorphous materials with a sufficiently low dielectric loss, which are essential for next-generation communication devices, the applicability of a nonequilibrium molecular dynamics simulation employing an external alternating electric field was examined using alkaline silicate glass models. In this method, the dielectric loss is directly evaluated as the phase shift of the dipole moment from the applied electric field. This method enabled us to evaluate the dielectric loss in a wide frequency range from 1 GHz to 10 THz. It was observed that the dielectric loss reaches its maximum at a few THz. The simulation method was found to qualitatively reproduce the effects of alkaline content and alkaline type on the dielectric loss. Furthermore, it reasonably reproduced the effect of mixed alkalines on the dielectric loss, which was observed in our experiments on sodium and/or potassium silicate glasses. Alkaline mixing was thus found to reduce the dielectric loss.  相似文献   
14.
Leucine-rich repeat kinase 2 (LRRK2) is a major causative gene of late-onset familial Parkinson’s disease (PD). The suppression of kinase activity is believed to confer neuroprotection, as most pathogenic variants of LRRK2 associated with PD exhibit increased kinase activity. We herein report a novel LRRK2 variant—p.G2294R—located in the WD40 domain, detected through targeted gene-panel screening in a patient with familial PD. The proband showed late-onset Parkinsonism with dysautonomia and a good response to levodopa, without cognitive decline or psychosis. Cultured cell experiments revealed that p.G2294R is highly destabilized at the protein level. The LRRK2 p.G2294R protein expression was upregulated in the patient’s peripheral blood lymphocytes. However, macrophages differentiated from the same peripheral blood showed decreased LRRK2 protein levels. Moreover, our experiment indicated reduced phagocytic activity in the pathogenic yeasts and α-synuclein fibrils. This PD case presents an example wherein the decrease in LRRK2 activity did not act in a neuroprotective manner. Further investigations are needed in order to elucidate the relationship between LRRK2 expression in the central nervous system and the pathogenesis caused by altered LRRK2 activity.  相似文献   
15.
16.
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   
17.
18.
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   
19.
The germline carrier of the BRCA1 pathogenic mutation has been well proven to confer an increased risk of breast and ovarian cancer. Despite BRCA1 biallelic pathogenic mutations being extremely rare, they have been reported to be embryonically lethal or to cause Fanconi anemia (FA). Here we describe a patient who was a 48-year-old female identified with biallelic pathogenic mutations of the BRCA1 gene, with no or very subtle FA-features. She was diagnosed with ovarian cancer and breast cancer at the ages of 43 and 44 and had a strong family history of breast and gynecological cancers.  相似文献   
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号