全文获取类型
收费全文 | 12991篇 |
免费 | 99篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 166篇 |
综合类 | 4篇 |
化学工业 | 809篇 |
金属工艺 | 339篇 |
机械仪表 | 82篇 |
建筑科学 | 248篇 |
矿业工程 | 21篇 |
能源动力 | 102篇 |
轻工业 | 156篇 |
水利工程 | 45篇 |
石油天然气 | 19篇 |
无线电 | 486篇 |
一般工业技术 | 490篇 |
冶金工业 | 892篇 |
原子能技术 | 109篇 |
自动化技术 | 9142篇 |
出版年
2021年 | 32篇 |
2020年 | 20篇 |
2019年 | 52篇 |
2018年 | 44篇 |
2017年 | 55篇 |
2016年 | 52篇 |
2015年 | 45篇 |
2014年 | 251篇 |
2013年 | 352篇 |
2012年 | 832篇 |
2011年 | 3159篇 |
2010年 | 1214篇 |
2009年 | 1095篇 |
2008年 | 768篇 |
2007年 | 687篇 |
2006年 | 535篇 |
2005年 | 676篇 |
2004年 | 593篇 |
2003年 | 667篇 |
2002年 | 338篇 |
2001年 | 77篇 |
2000年 | 50篇 |
1999年 | 78篇 |
1998年 | 180篇 |
1997年 | 79篇 |
1996年 | 67篇 |
1995年 | 44篇 |
1994年 | 44篇 |
1993年 | 43篇 |
1992年 | 36篇 |
1991年 | 33篇 |
1990年 | 45篇 |
1989年 | 37篇 |
1988年 | 37篇 |
1987年 | 51篇 |
1986年 | 36篇 |
1985年 | 51篇 |
1984年 | 40篇 |
1983年 | 35篇 |
1982年 | 37篇 |
1981年 | 32篇 |
1980年 | 26篇 |
1979年 | 34篇 |
1978年 | 34篇 |
1977年 | 33篇 |
1976年 | 49篇 |
1975年 | 30篇 |
1974年 | 32篇 |
1973年 | 42篇 |
1972年 | 23篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
Corey R. Nelson Tyler Mrozowich Sean M. Park Simmone Dsouza Amy Henrickson Justin R. J. Vigar Hans-Joachim Wieden Raymond J. Owens Borries Demeler Trushar R. Patel 《International journal of molecular sciences》2021,22(1)
Rift Valley fever virus (RVFV) is a mosquito-transmitted virus from the Bunyaviridae family that causes high rates of mortality and morbidity in humans and ruminant animals. Previous studies indicated that DEAD-box helicase 17 (DDX17) restricts RVFV replication by recognizing two primary non-coding RNAs in the S-segment of the genome: the intergenic region (IGR) and 5′ non-coding region (NCR). However, we lack molecular insights into the direct binding of DDX17 with RVFV non-coding RNAs and information on the unwinding of both non-coding RNAs by DDX17. Therefore, we performed an extensive biophysical analysis of the DDX17 helicase domain (DDX17135–555) and RVFV non-coding RNAs, IGR and 5’ NCR. The homogeneity studies using analytical ultracentrifugation indicated that DDX17135–555, IGR, and 5’ NCR are pure. Next, we performed small-angle X-ray scattering (SAXS) experiments, which suggested that DDX17 and both RNAs are homogenous as well. SAXS analysis also demonstrated that DDX17 is globular to an extent, whereas the RNAs adopt an extended conformation in solution. Subsequently, microscale thermophoresis (MST) experiments were performed to investigate the direct binding of DDX17 to the non-coding RNAs. The MST experiments demonstrated that DDX17 binds with the IGR and 5’ NCR with a dissociation constant of 5.77 ± 0.15 µM and 9.85 ± 0.11 µM, respectively. As DDX17135–555 is an RNA helicase, we next determined if it could unwind IGR and NCR. We developed a helicase assay using MST and fluorescently-labeled oligos, which suggested DDX17135–555 can unwind both RNAs. Overall, our study provides direct evidence of DDX17135–555 interacting with and unwinding RVFV non-coding regions. 相似文献
2.
3.
4.
5.
Sharma Nitin Kumar Kannan Rangasayee Li Leijun Anderson Neil Rashid Muhammad Collins Laurie Poplawsky Jonathan D. Unocic Raymond 《Metallurgical and Materials Transactions A》2021,52(9):3788-3798
Metallurgical and Materials Transactions A - The bondline of electric-resistance-welded (ERW) linepipe steel, often etched white (i.e., ferrite) in optical microscopy, is generally believed to be... 相似文献
6.
7.
Scientometrics - Short communications are an integral part of academic journal publishing since they serve as a forum for scholarly debate on recently published journal articles. Their prestige and... 相似文献
8.
Sven Schlumpberger Raymond B. Smith Huanhuan Tian Ali Mani Martin Z. Bazant 《American Institute of Chemical Engineers》2021,67(8):e17274
Shock electrodialysis is a recently developed electrochemical water treatment method that shows promise for water deionization and ionic separations. Although simple models and scaling laws have been proposed, a predictive theory has not yet emerged to fit experimental data and enable system design. Here, we extend and analyze existing “leaky membrane” models for the canonical case of a steady shock in crossflow, as in recent experimental prototypes. Two-dimensional numerical solutions are compared with analytical boundary-layer approximations and experimental data. The boundary-layer theory accurately reproduces the simulation results for desalination, and both models predict the data collapse of the desalination factor with dimensionless current, scaled to the incoming convective flux of cations. The numerical simulation also predicts the water recovery increase with current. Nevertheless, neither approach can quantitatively fit the transition from normal to over-limiting current, which suggests gaps in our understanding of extreme electrokinetic phenomena in porous media. 相似文献
9.
Tan Raymond R. Aviso Kathleen B. Lao Angelyn R. Promentilla Michael Angelo B. 《Clean Technologies and Environmental Policy》2022,24(1):173-184
Clean Technologies and Environmental Policy - P-graph causality maps were recently proposed as a methodology for systematic analysis of intertwined causal chains forming network-like structures.... 相似文献
10.
Belmonte Beatriz A. Aviso Kathleen B. Benjamin Michael Francis D. Tan Raymond R. 《Clean Technologies and Environmental Policy》2022,24(1):289-301
Clean Technologies and Environmental Policy - Biochar application and enhanced weathering are negative emission technologies (NETs) with the potential for large-scale deployment for the removal of... 相似文献