全文获取类型
收费全文 | 156302篇 |
免费 | 12805篇 |
国内免费 | 6958篇 |
专业分类
电工技术 | 8743篇 |
技术理论 | 3篇 |
综合类 | 8379篇 |
化学工业 | 24878篇 |
金属工艺 | 8560篇 |
机械仪表 | 10103篇 |
建筑科学 | 9428篇 |
矿业工程 | 3326篇 |
能源动力 | 5249篇 |
轻工业 | 11063篇 |
水利工程 | 2812篇 |
石油天然气 | 4949篇 |
武器工业 | 1285篇 |
无线电 | 22081篇 |
一般工业技术 | 21469篇 |
冶金工业 | 9684篇 |
原子能技术 | 2171篇 |
自动化技术 | 21882篇 |
出版年
2024年 | 481篇 |
2023年 | 1828篇 |
2022年 | 3517篇 |
2021年 | 5262篇 |
2020年 | 3877篇 |
2019年 | 3415篇 |
2018年 | 3935篇 |
2017年 | 4386篇 |
2016年 | 4531篇 |
2015年 | 5514篇 |
2014年 | 7427篇 |
2013年 | 9726篇 |
2012年 | 10616篇 |
2011年 | 12122篇 |
2010年 | 10663篇 |
2009年 | 10536篇 |
2008年 | 10396篇 |
2007年 | 9680篇 |
2006年 | 9001篇 |
2005年 | 7301篇 |
2004年 | 5819篇 |
2003年 | 4958篇 |
2002年 | 4811篇 |
2001年 | 3969篇 |
2000年 | 3306篇 |
1999年 | 2692篇 |
1998年 | 3097篇 |
1997年 | 2187篇 |
1996年 | 1830篇 |
1995年 | 1479篇 |
1994年 | 1120篇 |
1993年 | 994篇 |
1992年 | 695篇 |
1991年 | 657篇 |
1990年 | 540篇 |
1989年 | 521篇 |
1988年 | 388篇 |
1987年 | 332篇 |
1986年 | 309篇 |
1985年 | 253篇 |
1984年 | 219篇 |
1983年 | 179篇 |
1982年 | 171篇 |
1981年 | 149篇 |
1980年 | 144篇 |
1979年 | 110篇 |
1978年 | 97篇 |
1977年 | 131篇 |
1976年 | 161篇 |
1975年 | 81篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Jun Ogata Kentaro Hirao Kenya Nishioka Arisa Hayashida Yuanzhe Li Hiroyo Yoshino Soichiro Shimizu Nobutaka Hattori Yuzuru Imai 《International journal of molecular sciences》2021,22(7)
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
22.
23.
Young Been Kim Sung Hyeon Jung Dong Su Kim Nishad G. Deshpande Hee Won Suh Hak Hyeon Lee Ji Hoon Choi Ho Seong Lee Hyung Koun Cho 《Advanced functional materials》2021,31(38):2102439
Antimony triselenide (Sb2Se3) nanoflake-based nitrogen dioxide (NO2) sensors exhibit a progressive bifunctional gas-sensing performance, with a rapid alarm for hazardous highly concentrated gases, and an advanced memory-type function for low-concentration (<1 ppm) monitoring repeated under potentially fatal exposure. Rectangular and cuboid shaped Sb2Se3 nanoflakes, comprising van der Waals planes with large surface areas and covalent bond planes with small areas, can rapidly detect a wide range of NO2 gas concentrations from 0.1 to 100 ppm. These Sb2Se3 nanoflakes are found to be suitable for physisorption-based gas sensing owing to their anisotropic quasi-2D crystal structure with extremely enlarged van der Waals planes, where they are humidity-insensitive and consequently exhibit an extremely stable baseline current. The Sb2Se3 nanoflake sensor exhibits a room-temperature/low-voltage operation, which is noticeable owing to its low energy consumption and rapid response even under a NO2 gas flow of only 1 ppm. As a result, the Sb2Se3 nanoflake sensor is suitable for the development of a rapid alarm system. Furthermore, the persistent gas-sensing conductivity of the sensor with a slow decaying current can enable the development of a progressive memory-type sensor that retains the previous signal under irregular gas injection at low concentrations. 相似文献
24.
25.
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
26.
Cheng-Chin Huang Ching-Yao Yang Chin-Chuan Su Kai-Min Fang Cheng-Chieh Yen Ching-Ting Lin Jui-Min Liu Kuan-I Lee Ya-Wen Chen Shing-Hwa Liu Chun-Fa Huang 《International journal of molecular sciences》2021,22(9)
4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP), a major active metabolite of bisphenol A (BPA), is generated in the mammalian liver. Some studies have suggested that MBP exerts greater toxicity than BPA. However, the mechanism underlying MBP-induced pancreatic β-cell cytotoxicity remains largely unclear. This study demonstrated the cytotoxicity of MBP in pancreatic β-cells and elucidated the cellular mechanism involved in MBP-induced β-cell death. Our results showed that MBP exposure significantly reduced cell viability, caused insulin secretion dysfunction, and induced apoptotic events including increased caspase-3 activity and the expression of active forms of caspase-3/-7/-9 and PARP protein. In addition, MBP triggered endoplasmic reticulum (ER) stress, as indicated by the upregulation of GRP 78, CHOP, and cleaved caspase-12 proteins. Pretreatment with 4-phenylbutyric acid (4-PBA; a pharmacological inhibitor of ER stress) markedly reversed MBP-induced ER stress and apoptosis-related signals. Furthermore, exposure to MBP significantly induced the protein phosphorylation of JNK and AMP-activated protein kinase (AMPK)α. Pretreatment of β-cells with pharmacological inhibitors for JNK (SP600125) and AMPK (compound C), respectively, effectively abrogated the MBP-induced apoptosis-related signals. Both JNK and AMPK inhibitors also suppressed the MBP-induced activation of JNK and AMPKα and of each other. In conclusion, these findings suggest that MBP exposure exerts cytotoxicity on β-cells via the interdependent activation of JNK and AMPKα, which regulates the downstream apoptotic signaling pathway. 相似文献
27.
28.
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
29.
30.
Fluorescence‐Activated Cell Sorters: Standing Surface Acoustic Wave (SSAW)‐Based Fluorescence‐Activated Cell Sorter (Small 40/2018) 下载免费PDF全文