全文获取类型
收费全文 | 13228篇 |
免费 | 1259篇 |
国内免费 | 226篇 |
专业分类
电工技术 | 385篇 |
综合类 | 347篇 |
化学工业 | 3129篇 |
金属工艺 | 546篇 |
机械仪表 | 561篇 |
建筑科学 | 656篇 |
矿业工程 | 171篇 |
能源动力 | 423篇 |
轻工业 | 1737篇 |
水利工程 | 154篇 |
石油天然气 | 202篇 |
武器工业 | 22篇 |
无线电 | 1190篇 |
一般工业技术 | 2450篇 |
冶金工业 | 625篇 |
原子能技术 | 112篇 |
自动化技术 | 2003篇 |
出版年
2024年 | 59篇 |
2023年 | 223篇 |
2022年 | 439篇 |
2021年 | 629篇 |
2020年 | 476篇 |
2019年 | 366篇 |
2018年 | 573篇 |
2017年 | 583篇 |
2016年 | 669篇 |
2015年 | 556篇 |
2014年 | 704篇 |
2013年 | 1202篇 |
2012年 | 864篇 |
2011年 | 977篇 |
2010年 | 745篇 |
2009年 | 752篇 |
2008年 | 704篇 |
2007年 | 637篇 |
2006年 | 543篇 |
2005年 | 419篇 |
2004年 | 321篇 |
2003年 | 315篇 |
2002年 | 326篇 |
2001年 | 201篇 |
2000年 | 167篇 |
1999年 | 131篇 |
1998年 | 143篇 |
1997年 | 106篇 |
1996年 | 107篇 |
1995年 | 104篇 |
1994年 | 69篇 |
1993年 | 71篇 |
1992年 | 54篇 |
1991年 | 47篇 |
1990年 | 34篇 |
1989年 | 32篇 |
1988年 | 29篇 |
1987年 | 21篇 |
1986年 | 16篇 |
1985年 | 34篇 |
1984年 | 20篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 27篇 |
1980年 | 19篇 |
1979年 | 21篇 |
1978年 | 15篇 |
1977年 | 17篇 |
1976年 | 15篇 |
1974年 | 14篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
22.
23.
Yu Zhang Xiaofei Dai Haonan Jin Chaoxin Man Yujun Jiang 《Journal of dairy science》2021,104(4):4023-4032
This study aimed to predict the optimal carbon source for higher production of exopolysaccharides (EPS) by Lactobacillus paracasei TD 062, and to evaluate the effect of this carbon source on the production and monosaccharide composition of EPS. We evaluated the EPS production capacity of 20 strains of L. paracasei under the same conditions. We further investigated L. paracasei TD 062, which showed the highest EPS-producing activity (0.609 g/L), by examining the associated biosynthesis pathways for EPS. Genomics revealed that fructose, mannose, trehalose, glucose, galactose, and lactose were carbon sources that L. paracasei TD 062 could use to produce EPS. We identified an EPS synthesis gene cluster that could participate in transport, export, and sugar chain synthesis, and generate 6 sugar nucleotides. Experimental results showed that the sugar content of the EPS produced using fermentation with the optimized carbon source (fructose, mannose, trehalose, glucose, galactose, and lactose) increased by 115%. Furthermore, use of the optimized carbon source changed the monosaccharide content of the associated EPS. The results of enzyme activity measurements showed significant increases in the activity of 2 key enzymes involved in the glycoside synthesis pathway. Our study revealed that optimizing the carbon source provided for fermentation not only increased the production of EPS, but also affected the composition of the monosaccharides by increasing enzyme activity in the underlying synthesis pathways, suggesting an important role for carbon source in the production of EPS by L. paracasei TD 062. 相似文献
24.
25.
Alfredo M. Gravagnuolo Eden Morales‐Narváez Charlene Regina Santos Matos Sara Longobardi Paola Giardina Arben Merkoçi 《Advanced functional materials》2015,25(38):6084-6092
Class I hydrophobin Vmh2, a peculiar surface active and versatile fungal protein, is known to self‐assemble into chemically stable amphiphilic films, to be able to change wettability of surfaces, and to strongly adsorb other proteins. Herein, a fast, highly homogeneous and efficient glass functionalization by spontaneous self‐assembling of Vmh2 at liquid–solid interfaces is achieved (in 2 min). The Vmh2‐coated glass slides are proven to immobilize not only proteins but also nanomaterials such as graphene oxide (GO) and quantum dots (QDs). As models, bovine serum albumin labeled with Alexa 555 fluorophore, anti‐immunoglobulin G antibodies, and cadmium telluride QDs are patterned in a microarray fashion in order to demonstrate functionality, reproducibility, and versatility of the proposed substrate. Additionally, a GO layer is effectively and homogeneously self‐assembled onto the studied functionalized surface. This approach offers a quick and simple alternative to immobilize nanomaterials and proteins, which is appealing for new bioanalytical and nanobioenabled applications. 相似文献
26.
27.
The Journal of Supercomputing - Deep learning algorithms have yielded remarkable results in medical diagnosis and image analysis, besides their contribution to improvements in a number of fields... 相似文献
28.
Özge Seçmeler Özlem Güçlü Üstündağ 《International Journal of Food Science & Technology》2019,54(5):1609-1616
The partitioning of predominant lipophilic olive bioactives (squalene, β-sitosterol and α-tocopherol) in olive oil processing was studied for the first time using common integrated olive milling plant. 7% of the oil and 5% of the squalene present in the olives was lost in the last pomace. β-sitosterol and α-tocopherol, which are mainly concentrated in the seed of the olive fruit, was recovered in virgin olive oil to a lesser extent (66%, 67%) while 10% were lost in last pomace. Thus, the loss of β-sitosterol and α-tocopherol was higher than that of squalene and oil, due to nonrecovered bound forms. 19% of the α-tocopherol and 21% of the β-sitosterol loss was unaccounted for, which can be attributed to degradation of α-tocopherol and incomplete recovery of sterols from the olive and pomace matrices. This study provides a basis for process development studies. 相似文献
29.
介绍了书籍装订热熔胶生产工艺及产品的技术指标,对1000t/a生产装置的投资与产品成本进行了核算。分析结果表明,总投资110万元,年利润达266万元。 相似文献
30.
A monitoring of tool wear in different cutting operations has been studied for many years. Special techniques have been used to detect a wear status basing upon cutting forces, acoustic emission, temperature, torque and power, vibration, noise and acceleration sensors. The adapting of a proper prediction method allows to solve problems of an automatic supervision in Computer Integrated Manufacturing systems. A task of the abrasive edge wear index prediction can be formulated as follows: disposing by the data collection of the edge wear status in a time period preceding the concerning the wear status in the successive time period embraced by the prediction method. 相似文献