全文获取类型
收费全文 | 3092篇 |
免费 | 258篇 |
国内免费 | 1713篇 |
专业分类
化学 | 3742篇 |
晶体学 | 21篇 |
力学 | 50篇 |
综合类 | 102篇 |
数学 | 251篇 |
物理学 | 897篇 |
出版年
2024年 | 21篇 |
2023年 | 74篇 |
2022年 | 105篇 |
2021年 | 96篇 |
2020年 | 75篇 |
2019年 | 102篇 |
2018年 | 67篇 |
2017年 | 87篇 |
2016年 | 102篇 |
2015年 | 99篇 |
2014年 | 212篇 |
2013年 | 187篇 |
2012年 | 200篇 |
2011年 | 204篇 |
2010年 | 205篇 |
2009年 | 237篇 |
2008年 | 228篇 |
2007年 | 205篇 |
2006年 | 245篇 |
2005年 | 206篇 |
2004年 | 247篇 |
2003年 | 214篇 |
2002年 | 182篇 |
2001年 | 189篇 |
2000年 | 135篇 |
1999年 | 112篇 |
1998年 | 139篇 |
1997年 | 134篇 |
1996年 | 116篇 |
1995年 | 92篇 |
1994年 | 87篇 |
1993年 | 91篇 |
1992年 | 93篇 |
1991年 | 64篇 |
1990年 | 67篇 |
1989年 | 66篇 |
1988年 | 26篇 |
1987年 | 18篇 |
1986年 | 12篇 |
1985年 | 8篇 |
1984年 | 6篇 |
1983年 | 7篇 |
1982年 | 1篇 |
排序方式: 共有5063条查询结果,搜索用时 62 毫秒
91.
92.
Chao Feng Zhang Li Fan Pin Yang 《中国化学快报》2007,18(1):97-98
Zinc may play a role as a co-factor in the pathogenesis of Alzheimer's disease(AD)through influencing the conformation and neurotoxicity of amyloidβ-protein(Aβ).Using the fluorescamine assay,we show for the first time that Zn~(2 )induced Aβ(10-21) aggregate in a concentration-dependent manner.These results indicate that Aβ(10-21)can be used as an in vitro model in Zn~(2 )- induced Aβaggregation and that the region 10-21 to be the minimal fragment of zinc-binding domain of full length Aβ(1-42). 相似文献
93.
A three-dimensional pharmacophore model was developed from a series of inhibitors of Aurora A kinase to discover new potent anti-cancer agents using the HypoGen module in the Catalyst software. The pharmacophore model was developed based on the structure of 20 currently available inhibitors, which were carefully selected from the literature. The best hypothesis (Hypo 1) was defined by four features: one hydrogen-bond donor and three hy- drophobic points, with the best correlation coefficient of 0.909, the lowest rms deviation of 1.563, and the highest cost difference of 99.075. The Hypo 1 was then validated by a test set consisting of 24 compounds and by a cross-validation of 95% confidence level through randomizing the data using the CatScramble program, which suggested that a predictive pharmacophore model had been successfully obtained. 相似文献
94.
笼形聚偕胺肟树脂的研究HX/ACAO树脂吸附贵金属 总被引:3,自引:0,他引:3
氢卤酸、硝酸、硫酸、磷酸和硼酸处理的笼形聚偕胺肟树脂(HX/A-CAO)对Ag+和等贵金属离子的吸附能力按如下顺序:PdCl42-:H3BO3/ACAO>BCAO>H3PO4/ACAO>HI/ACAO>H2SO4/ACAO>HCl/ACAO>HNO3/ACAO>HF/ACAO.IrCl62-:BCAO>H3PO4/ACAO>H3BO3/ACAO>HCl/ACAO>HF/ACAO>HI/ACAO>H2SO4/ACAO≥HNO3/ACAO.PtCl62:BCAO>H3BO3/ACAO>H2SO4/ACAO>HNO3/ACAO>HCl/ACAO>HF/ACAO>H3PO4/ACAO>HI/ACAO.Ag+:BCAO>H3BO3/ACAO>HI/ACAO>H2SO4/ACAO>HF/ACAO>HCl/ACAO>H3PO4/ACAO>HNO3/ACAO.AuCl4-:BCAO>H3BO3>H3PO4/ACAO>HF/ACAO>HCl/A-CAO>H2SO4/ACAO>HI/ACAO>HNO3/A-CAO.研究了H3BO3/ACAO树脂对Ag+和离子的吸附动力学,讨论了吸附机理. 相似文献
95.
96.
97.
98.
Knoevenagel condensation catalysed by poly(vinyl chloride) supported tetraethylenepentamine (PVC-TEPA) 总被引:1,自引:0,他引:1
Fen Dong Yi Qun Li Rong Feng Dai 《中国化学快报》2007,18(3):266-268
Poly(vinyl chloride) supported tetraethylenepentamine (PVC-TEPA) has been found to be an efficient catalyst for the Knoevenagel condensation. A wide range of aromatic aldehydes easily undergo condensations with ethyl cyanoacetate and malononitrile in the commercial 95% ethanol in refluxing using PVC-TEPA as catalyst to afford the desired products of good purity in moderate to excellent yields. A recycling study confirmed that the catalyst could be reused, the yield of the desired condensation product were not reduced. The merits of this protocol are environmentally benign, simple operation, convenient work-up and good yields. Furthermore, the catalyst can easily be recovered and reused at five times with comparable yields. 相似文献
99.
100.