全文获取类型
收费全文 | 15870篇 |
免费 | 2000篇 |
国内免费 | 847篇 |
专业分类
电工技术 | 881篇 |
综合类 | 1073篇 |
化学工业 | 2833篇 |
金属工艺 | 333篇 |
机械仪表 | 1225篇 |
建筑科学 | 1133篇 |
矿业工程 | 216篇 |
能源动力 | 524篇 |
轻工业 | 1085篇 |
水利工程 | 81篇 |
石油天然气 | 904篇 |
武器工业 | 98篇 |
无线电 | 4069篇 |
一般工业技术 | 2532篇 |
冶金工业 | 290篇 |
原子能技术 | 205篇 |
自动化技术 | 1235篇 |
出版年
2024年 | 229篇 |
2023年 | 356篇 |
2022年 | 511篇 |
2021年 | 613篇 |
2020年 | 654篇 |
2019年 | 609篇 |
2018年 | 529篇 |
2017年 | 673篇 |
2016年 | 719篇 |
2015年 | 712篇 |
2014年 | 1087篇 |
2013年 | 976篇 |
2012年 | 1073篇 |
2011年 | 1125篇 |
2010年 | 920篇 |
2009年 | 937篇 |
2008年 | 855篇 |
2007年 | 865篇 |
2006年 | 803篇 |
2005年 | 695篇 |
2004年 | 595篇 |
2003年 | 562篇 |
2002年 | 425篇 |
2001年 | 361篇 |
2000年 | 359篇 |
1999年 | 265篇 |
1998年 | 221篇 |
1997年 | 167篇 |
1996年 | 132篇 |
1995年 | 112篇 |
1994年 | 118篇 |
1993年 | 103篇 |
1992年 | 62篇 |
1991年 | 46篇 |
1990年 | 50篇 |
1989年 | 32篇 |
1988年 | 23篇 |
1987年 | 12篇 |
1986年 | 20篇 |
1985年 | 23篇 |
1984年 | 28篇 |
1983年 | 16篇 |
1982年 | 17篇 |
1981年 | 3篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1964年 | 2篇 |
1959年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 14 毫秒
21.
22.
Genetic Dissection of Light-Regulated Adventitious Root Induction in Arabidopsis thaliana Hypocotyls
Yinwei Zeng Sebastien Schotte Hoang Khai Trinh Inge Verstraeten Jing Li Ellen Van de Velde Steffen Vanneste Danny Geelen 《International journal of molecular sciences》2022,23(10)
Photomorphogenic responses of etiolated seedlings include the inhibition of hypocotyl elongation and opening of the apical hook. In addition, dark-grown seedlings respond to light by the formation of adventitious roots (AR) on the hypocotyl. How light signaling controls adventitious rooting is less well understood. Hereto, we analyzed adventitious rooting under different light conditions in wild type and photomorphogenesis mutants in Arabidopsis thaliana. Etiolation was not essential for AR formation but raised the competence to form AR under white and blue light. The blue light receptors CRY1 and PHOT1/PHOT2 are key elements contributing to the induction of AR formation in response to light. Furthermore, etiolation-controlled competence for AR formation depended on the COP9 signalosome, E3 ubiquitin ligase CONSTITUTIVELY PHOTOMORPHOGENIC (COP1), the COP1 interacting SUPPRESSOR OF PHYA-105 (SPA) kinase family members (SPA1,2 and 3) and Phytochrome-Interacting Factors (PIF). In contrast, ELONGATED HYPOCOTYL5 (HY5), suppressed AR formation. These findings provide a genetic framework that explains the high and low AR competence of Arabidopsis thaliana hypocotyls that were treated with dark, and light, respectively. We propose that light-induced auxin signal dissipation generates a transient auxin maximum that explains AR induction by a dark to light switch. 相似文献
23.
24.
25.
26.
Magda Pl Kamirn ron Hamow Altafur Rahman Imre Majlth Judit Tajti Orsolya Kinga Gondor Mohamed Ahres Fatemeh Gholizadeh Gabriella Szalai Tibor Janda 《International journal of molecular sciences》2022,23(15)
Although light-emitting diode (LED) technology has extended the research on targeted photomorphogenic, physiological, and biochemical responses in plants, there is not enough direct information about how light affects polyamine metabolism. In this study, the effect of three spectral compositions (referred to by their most typical characteristic: blue, red, and the combination of blue and red [pink] lights) on polyamine metabolism was compared to those obtained under white light conditions at the same light intensity. Although light quality induced pronounced differences in plant morphology, pigment contents, and the expression of polyamine metabolism-related genes, endogenous polyamine levels did not differ substantially. When exogenous polyamines were applied, their roborative effect were detected under all light conditions, but these beneficial changes were correlated with an increase in polyamine content and polyamine metabolism-related gene expression only under blue light. The effect of the polyamines on leaf gene expression under red light was the opposite, with a decreasing tendency. Results suggest that light quality may optimize plant growth through the adjustment of polyamine metabolism at the gene expression level. Polyamine treatments induced different strategies in fine-tuning of polyamine metabolism, which were induced for optimal plant growth and development under different spectral compositions. 相似文献
27.
介绍了国家标准GB 7000.217-2008/IEC 60598-2-17:1984+A2:1990《灯具第2-17部分:特殊要求舞台灯光、电视、电影及摄影场所(室内外)用灯具》的特殊要求,阐述了对该标准特殊要求条文的理解和解释以及其对LED舞台灯具的适用性,以帮助舞台灯具行业的设计、生产、检验和使用人员正确理解和应用舞台灯具国家标准。 相似文献
28.
29.
30.
Youngjae Ryu Yoonju Kim Hye Ryeong Lim Hyung-Joon Kim Byong Seo Park Jae Geun Kim Sang-Joon Park Chang Man Ha 《International journal of molecular sciences》2022,23(12)
Recent advances in optical clearing techniques have dramatically improved deep tissue imaging by reducing the obscuring effects of light scattering and absorption. However, these optical clearing methods require specialized equipment or a lengthy undertaking with complex protocols that can lead to sample volume changes and distortion. In addition, the imaging of cleared tissues has limitations, such as fluorescence bleaching, harmful and foul-smelling solutions, and the difficulty of handling samples in high-viscosity refractive index (RI) matching solutions. To address the various limitations of thick tissue imaging, we developed an Aqueous high refractive Index matching and tissue Clearing solution for Imaging (termed AICI) with a one-step tissue clearing protocol that was easily made at a reasonable price in our own laboratory without any equipment. AICI can rapidly clear a 1 mm thick brain slice within 90 min with simultaneous RI matching, low viscosity, and a high refractive index (RI = 1.466), allowing the imaging of the sample without additional processing. We compared AICI with commercially available RI matching solutions, including optical clear agents (OCAs), for tissue clearing. The viscosity of AICI is closer to that of water compared with other RI matching solutions, and there was a less than 2.3% expansion in the tissue linear morphology during 24 h exposure to AICI. Moreover, AICI remained fluid over 30 days of air exposure, and the EGFP fluorescence signal was only reduced to ~65% after 10 days. AICI showed a limited clearing of brain tissue >3 mm thick. However, fine neuronal structures, such as dendritic spines and axonal boutons, could still be imaged in thick brain slices treated with AICI. Therefore, AICI is useful not only for the three-dimensional (3D) high-resolution identification of neuronal structures, but also for the examination of multiple structural imaging by neuronal distribution, projection, and gene expression in deep brain tissue. AICI is applicable beyond the imaging of fluorescent antibodies and dyes, and can clear a variety of tissue types, making it broadly useful to researchers for optical imaging applications. 相似文献