全文获取类型
收费全文 | 105053篇 |
免费 | 7195篇 |
国内免费 | 2509篇 |
专业分类
电工技术 | 3855篇 |
技术理论 | 2篇 |
综合类 | 3079篇 |
化学工业 | 19028篇 |
金属工艺 | 4946篇 |
机械仪表 | 6265篇 |
建筑科学 | 4714篇 |
矿业工程 | 1507篇 |
能源动力 | 3607篇 |
轻工业 | 7303篇 |
水利工程 | 1030篇 |
石油天然气 | 3015篇 |
武器工业 | 401篇 |
无线电 | 15686篇 |
一般工业技术 | 17493篇 |
冶金工业 | 8410篇 |
原子能技术 | 1201篇 |
自动化技术 | 13215篇 |
出版年
2024年 | 228篇 |
2023年 | 1361篇 |
2022年 | 2427篇 |
2021年 | 3695篇 |
2020年 | 2658篇 |
2019年 | 2564篇 |
2018年 | 2919篇 |
2017年 | 2932篇 |
2016年 | 3193篇 |
2015年 | 3342篇 |
2014年 | 4560篇 |
2013年 | 6488篇 |
2012年 | 6277篇 |
2011年 | 7439篇 |
2010年 | 5825篇 |
2009年 | 5908篇 |
2008年 | 5706篇 |
2007年 | 4982篇 |
2006年 | 4797篇 |
2005年 | 4070篇 |
2004年 | 3370篇 |
2003年 | 3070篇 |
2002年 | 2977篇 |
2001年 | 2472篇 |
2000年 | 2291篇 |
1999年 | 2274篇 |
1998年 | 3080篇 |
1997年 | 2211篇 |
1996年 | 1875篇 |
1995年 | 1542篇 |
1994年 | 1173篇 |
1993年 | 992篇 |
1992年 | 750篇 |
1991年 | 706篇 |
1990年 | 604篇 |
1989年 | 570篇 |
1988年 | 431篇 |
1987年 | 356篇 |
1986年 | 308篇 |
1985年 | 277篇 |
1984年 | 241篇 |
1983年 | 197篇 |
1982年 | 187篇 |
1981年 | 163篇 |
1980年 | 159篇 |
1979年 | 122篇 |
1978年 | 111篇 |
1977年 | 132篇 |
1976年 | 178篇 |
1975年 | 93篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
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
32.
33.
Amino acid modified polyaspartic acids were evaluated as calcium-scale inhibitors. Feasibility of scale inhibition experiments was analyzed by molecular dynamics simulation and Gaussian optimization, and the scale inhibition mechanism was theoretically analyzed. Scale inhibition performance was studied by scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, static scale inhibition experiments, and electrochemical performance testing, which provided an experimental basis for the molecular dynamics simulation. The experimental results showed that Arg-SA-PASP has better scale inhibition and corrosion inhibition performance than His-SA-PASP. The scale inhibition effect increased with increasing concentration. Electrochemical tests indicated that Arg-SA-PASP is an excellent scale and corrosion inhibitor. 相似文献
34.
Salim Hengky K. Padfield Rory Lee Chew Tin Syayuti Khadijah Papargyropoulou Effie Tham Mun Hou 《Clean Technologies and Environmental Policy》2018,20(3):529-538
Clean Technologies and Environmental Policy - Food production and consumption is one of the major causes of global environmental degradation. One way to address environmental impacts in the food... 相似文献
35.
Lee Sangyul Kim Minjae Kim Hajin 《Journal of Mechanical Science and Technology》2018,32(12):5961-5972
Journal of Mechanical Science and Technology - The shape of the combustion chamber plays an important role in the formation of the air-fuel mixture in the chamber, which has a great influence on... 相似文献
36.
37.
Multimedia Systems - The preferences of Web information purchasers are changing. Cost-effectiveness (i.e., an emphasis on performance with respect to price) is becoming less regarded than... 相似文献
38.
The Journal of Supercomputing - Spark is one of the most widely used systems for the distributed processing of big data. Its performance bottlenecks are mainly due to the network I/O, disk I/O, and... 相似文献
39.
40.
Peer-to-Peer Networking and Applications - 相似文献