全文获取类型
收费全文 | 16179篇 |
免费 | 1593篇 |
国内免费 | 451篇 |
专业分类
电工技术 | 709篇 |
综合类 | 599篇 |
化学工业 | 3006篇 |
金属工艺 | 583篇 |
机械仪表 | 680篇 |
建筑科学 | 952篇 |
矿业工程 | 204篇 |
能源动力 | 522篇 |
轻工业 | 1438篇 |
水利工程 | 231篇 |
石油天然气 | 267篇 |
武器工业 | 126篇 |
无线电 | 1980篇 |
一般工业技术 | 2647篇 |
冶金工业 | 1297篇 |
原子能技术 | 126篇 |
自动化技术 | 2856篇 |
出版年
2024年 | 62篇 |
2023年 | 298篇 |
2022年 | 478篇 |
2021年 | 775篇 |
2020年 | 620篇 |
2019年 | 459篇 |
2018年 | 499篇 |
2017年 | 536篇 |
2016年 | 606篇 |
2015年 | 611篇 |
2014年 | 831篇 |
2013年 | 1185篇 |
2012年 | 1065篇 |
2011年 | 1173篇 |
2010年 | 869篇 |
2009年 | 849篇 |
2008年 | 1012篇 |
2007年 | 867篇 |
2006年 | 722篇 |
2005年 | 606篇 |
2004年 | 532篇 |
2003年 | 431篇 |
2002年 | 365篇 |
2001年 | 263篇 |
2000年 | 223篇 |
1999年 | 227篇 |
1998年 | 244篇 |
1997年 | 218篇 |
1996年 | 187篇 |
1995年 | 157篇 |
1994年 | 167篇 |
1993年 | 127篇 |
1992年 | 108篇 |
1991年 | 85篇 |
1990年 | 74篇 |
1989年 | 84篇 |
1988年 | 61篇 |
1987年 | 37篇 |
1986年 | 42篇 |
1985年 | 47篇 |
1984年 | 46篇 |
1983年 | 35篇 |
1982年 | 29篇 |
1981年 | 45篇 |
1980年 | 41篇 |
1979年 | 28篇 |
1978年 | 26篇 |
1977年 | 21篇 |
1976年 | 20篇 |
1974年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
1.
Quan Nguyen Minh Quoc Dat Lai Hoang Nguy Minh Minh Tu Tran Kieu Ngoc Lam Gia Uyen Le My Phung Hang Hoang Dung Nguyen Tran Diem Ai Chau Ngoc Thuc Trinh Doan 《International Journal of Food Science & Technology》2022,57(7):4507-4517
To prevent the adulteration of agricultural resources and provide a solution to enhance the green coffee bean supply chain, authentication using the near-infrared spectroscopy (NIRS) technique was investigated. Partial least square with discrimination analysis (PLS-DA) models combined with various preprocessing methods were built from NIR spectra of 153 Vietnamese green coffee samples. The model combined with the standard normal variate and the first order of derivative yielded excellent performance in predicting coffee species with the error cross-validation of 0.0261. PLS-DA model of mean centre and first-order derivative spectra also yielded good performance in verifying geographical indication of green coffee with the error of 0.0656. By contrast, the predicting abilities of post-harvest methods were poor. The overall results showed a high potential of the NIRS in online authentication practices. 相似文献
3.
Belcher Calvin H. Zheng Baolong MacDonald Benjamin E. Langlois Eric D. Lehman Benjamin Pearce Charles Delaney Robert Apelian Diran Lavernia Enrique J. Monson Todd C. 《Journal of Materials Science》2022,57(9):5518-5532
Journal of Materials Science - For transformers and inductors to meet the world’s growing demand for electrical power, more efficient soft magnetic materials with high saturation magnetic... 相似文献
4.
Bouaziz Youssef Royer Eric Bresson Guillaume Dhome Michel 《Multimedia Tools and Applications》2022,81(16):22449-22480
Multimedia Tools and Applications - Changes in appearance present a tremendous problem for the visual localization of an autonomous vehicle in outdoor environments. Data association between the... 相似文献
5.
Ava Kwong Cecilia Y. S. Ho Vivian Y. Shin Chun Hang Au Tsun Leung Chan Edmond S. K. Ma 《International journal of molecular sciences》2021,22(2)
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
6.
Nitsa Buaron Antonella Mangraviti Francesco Volpin Ann Liu Mariangela Pedone Eric Sankey Dina Aranovich Itay Adar Fausto J. Rodriguez Abraham Nyska Riki Goldbart Tamar Traitel Henry Brem Betty Tyler Joseph Kost 《Advanced functional materials》2021,31(44):2100643
Treating neuroinflammation-related injuries and disorders through manipulation of neuroinflammation functions is being heralded as a new therapeutic strategy. In this study, a novel pectic galactan (PG) polysaccharide based gene therapy approach is developed for targeting reactive gliosis in neuroinflammation. Galectin-3 (Gal-3) is a cell protein with a high affinity to β-galactoside sugars and is highly expressed in reactive gliosis. Since PG carries galactans, it can target reactive gliosis via specific carbohydrate interaction between galactan and Gal-3 on the cell membrane, and therefore can be utilized as a carrier for delivering genes to these cells. The carrier is synthesized by modifying quaternary ammonium groups on the PG. The resulting quaternized PG (QPG) is found to form complexes with plasmid DNA with a mean diameter of 100 nm and have the characteristics required for targeted gene therapy. The complexes efficiently condense large amounts of plasmid per particle and successfully bind to Gal-3. The in vivo study shows that the complexes are biocompatible and safe for administration and can selectively transfect reactive glial cells of an induced cortical lesion. The results confirm that this PG-based delivery system is a promising platform for targeting Gal-3 overexpressing neuroinflammation cells for treating neuroinflammation-related injuries and neurodegenerative diseases. 相似文献
7.
8.
聚乙二醇-三聚氰胺甲醛和聚乙烯醇半互穿网络的构建及表征 总被引:1,自引:0,他引:1
为提高三聚氰胺甲醛(MF)树脂制品的柔韧性,以聚乙二醇接枝三聚氰胺(M-PEG)替代部分三聚氰胺,并与甲醛、聚乙烯醇(PVA)在碱性条件下合成了聚乙二醇-三聚氰胺甲醛(PEG-MF)与PVA的半互穿聚合物网络体系(SemiIPN)。采用红外光谱、拉曼光谱、热重分析、差示扫描量热法等手段对Semi-IPN的微观结构进行了剖析,并分析了PEG、PVA等柔性链段对Semi-IPN黏度、游离甲醛含量、柔韧性等性能的影响。结果表明,PVA作为线型结构贯穿于聚乙二醇-三聚氰胺甲醛树脂交联网络体系结构中,形成了半互穿网络结构;所形成的Semi-IPN的热分解温度比MF树脂降低了60℃左右;Semi-IPN的韧性比纯MF树脂提高了800%,最高可达到19.700kJ/m2。 相似文献
9.
10.
Robert Creutznacher Eric Schulze Georg Wallmann Prof. Dr. Thomas Peters Dr. Matthias Stein Dr. Alvaro Mallagaray 《Chembiochem : a European journal of chemical biology》2020,21(7):1007-1021
Bile acids have been reported as important cofactors promoting human and murine norovirus (NoV) infections in cell culture. The underlying mechanisms are not resolved. Through the use of chemical shift perturbation (CSP) NMR experiments, we identified a low-affinity bile acid binding site of a human GII.4 NoV strain. Long-timescale MD simulations reveal the formation of a ligand-accessible binding pocket of flexible shape, allowing the formation of stable viral coat protein–bile acid complexes in agreement with experimental CSP data. CSP NMR experiments also show that this mode of bile acid binding has a minor influence on the binding of histo-blood group antigens and vice versa. STD NMR experiments probing the binding of bile acids to virus-like particles of seven different strains suggest that low-affinity bile acid binding is a common feature of human NoV and should therefore be important for understanding the role of bile acids as cofactors in NoV infection. 相似文献