全文获取类型
收费全文 | 323篇 |
免费 | 20篇 |
国内免费 | 9篇 |
专业分类
化学 | 239篇 |
晶体学 | 1篇 |
力学 | 14篇 |
数学 | 22篇 |
物理学 | 76篇 |
出版年
2023年 | 1篇 |
2022年 | 5篇 |
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 13篇 |
2018年 | 16篇 |
2017年 | 9篇 |
2016年 | 17篇 |
2015年 | 11篇 |
2014年 | 18篇 |
2013年 | 38篇 |
2012年 | 28篇 |
2011年 | 30篇 |
2010年 | 25篇 |
2009年 | 19篇 |
2008年 | 16篇 |
2007年 | 11篇 |
2006年 | 18篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 7篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1997年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1980年 | 3篇 |
排序方式: 共有352条查询结果,搜索用时 707 毫秒
21.
Smailii Parisa Pakroo Raziye Mohammadkhani Ramin Jafarian Vahab Kabiri Esfahani Farhad Hassani Leila 《Journal of the Iranian Chemical Society》2020,17(1):127-134
Journal of the Iranian Chemical Society - Herein, we investigated the interaction of cisplatin loaded on GO (GO@CDDP) with two regulatory sequences, BRCA1 and BRCA2, synthesized from ssDNA based on... 相似文献
22.
23.
To understand how proteins function on a cellular level, it is of paramount importance to understand their structures and dynamics, including the conformational changes they undergo to carry out their function. For the aforementioned reasons, the study of large conformational changes in proteins has been an interest to researchers for years. However, since some proteins experience rapid and transient conformational changes, it is hard to experimentally capture the intermediate structures. Additionally, computational brute force methods are computationally intractable, which makes it impossible to find these pathways which require a search in a high-dimensional, complex space. In our previous work, we implemented a hybrid algorithm that combines Monte-Carlo (MC) sampling and RRT*, a version of the Rapidly Exploring Random Trees (RRT) robotics-based method, to make the conformational exploration more accurate and efficient, and produce smooth conformational pathways. In this work, we integrated the rigidity analysis of proteins into our algorithm to guide the search to explore flexible regions. We demonstrate that rigidity analysis dramatically reduces the run time and accelerates convergence. 相似文献
24.
In this paper, a mild and green protocol has been developed for the synthesis of quinazoline derivatives. The catalytic activity of 7‐aminonaphthalene‐1,3‐disulfonic acid‐functionalized magnetic Fe3O4 nanoparticles (Fe3O4@SiO2@Propyl–ANDSA) was investigated in the one‐pot synthesis of new derivatives of tetrahydrotetrazolo[1,5‐a]quinazolines and tetrahydrobenzo[h]tetrazolo[5,1‐b]quinazolines from the reaction of aldehydes, 5‐aminotetrazole, and dimedone or 6‐methoxy‐3,4‐dihyronaphtalen‐1(2H)‐one at 100 °C in H2O/EtOH as the solvent. The catalyst was characterized before and after the organic reaction. Fe3O4@SiO2@Propyl–ANDSA showed remarkable advantages in comparison with previous methods. Advantages of the method presented here include easy purification, reusability of the catalyst, green and mild procedure, and synthesis of new derivatives in high yields within short reaction time. 相似文献
25.
Ramin Ghorbani-Vaghei Zahra Toghraei-Semiromi 《Phosphorus, sulfur, and silicon and the related elements》2013,188(8):1701-1707
N,N′-Diiodo-N,N′-1,2-ethanediylbis(p-toluenesulfonamide) (NIBTS) is a highly efficient catalyst for the acetylation of alcohols, phenols, amines, and thiols under solvent-free conditions. Primary, secondary, tertiary alcohols; phenols; amines; and thiols can be easily acetylated in good to excellent yields at 80 °C. 相似文献
26.
Ramin Ghorbani-Vaghei Ardeshir Khazaei 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):1787-1791
Aliphatic and aromatic 1,3-oxathiolanes[3pc] are readily oxidized to aldehydes and ketones in good yields under mild conditions by N,N′-dibromo-N,N′-1,2-ethanediylbis(p-toluenesulphonamide) [BNBTS]. 相似文献
27.
N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide (TBBDA)/triphenylphosphine and N,N,N',N'-tetra- chlorobenzene-1,3-disulfonamide (TCBDA)/triphenylphosphine have been introduced as highly efficient systems for the versatile conversion of aldoxime derivatives into nitriles. The process reported here is operationally simple and reactions have been mildly performed in dichloromethane at room temperature. 相似文献
28.
Hanieh Ghadimi Ramin M.A.TehraniAbdussalam Salhin Mohamed Ali Norita MohamedSulaiman Ab Ghani 《Analytica chimica acta》2013
A novel glassy carbon electrode (GCE) modified with a composite film of poly (4-vinylpyridine) (P4VP) and multiwalled carbon nanotubes (P4VP/MWCNT GCE) was used for the voltammetric determination of paracetamol (PCT). This novel electrode displayed a combined effect of P4VP and MWCNT on the electro-oxidation of PCT in a solution of phosphate buffer at pH 7. Hence, conducting properties of P4VP along with the remarkable physical properties of MWCNTs might have combined effects in enhancing the kinetics of PCT oxidation. The P4VP/MWCNT GCE has also demonstrated excellent electrochemical activity toward PCT oxidation compared to that with bare GCE and MWCNT GCE. The anodic peak currents of PCT on the P4VP/MWCNT GCE were about 300 fold higher than that of the non-modified electrodes. By applying differential pulse voltammetry technique under optimized experimental conditions, a good linear ratio of oxidation peak currents and concentrations of PCT over the range of 0.02–450 μM with a limit of detection of 1.69 nM were achieved. This novel electrode was stable for more than 60 days and reproducible responses were obtained at 99% of the initial current of PCT without any influence of physiologically common interferences such as ascorbic acid and uric acid. The application of this electrode to determine PCT in tablets and urine samples was proposed. 相似文献
29.
Mohammad Navid Soltani Rad Somayeh Behrouz Abdollah Movahedian Mohammad Mahdi Doroodmand Younes Ghasemi Sara Rasoul‐Amini Abdol‐Rasoul Ahmadi Gandomani Ramin Rezaie 《Helvetica chimica acta》2013,96(4):688-701
A facile and simple protocol for the 1,3‐dipolar cycloaddition of organic azides with terminal alkynes catalyzed by doped nano‐sized Cu2O on melamine? formaldehyde resin (nano‐Cu2O? MFR) as a new and convenient heterogeneous catalyst is described. In this method, ‘click’ cycloaddition of various structurally diverse β‐azido alcohols and alkynes in the presence of nano‐Cu2O? MFR in H2O/THF 1 : 2 furnished the corresponding 1,4‐disubstituted 1H‐1,2,3‐triazole adducts 1a – 1o in good to excellent yields at room temperature (Scheme and Table 3). The nano‐Cu2O? MFR was characterized by scanning electron microscopy (SEM), X‐ray diffraction (XRD), inductively coupled plasma (ICP) analysis, and FT‐IR. The nano‐Cu2O? MFR could be easily recovered and recycled from the reaction mixture and reused for many consecutive trials without significant decrease in activity (Table 4). The in vitro antibacterial activities of all synthesized compounds were tested on several Gram‐positive and/or Gram‐negative bacteria (Table 5). The results demonstrate the promising antibacterial activity for some of the synthesized compounds. 相似文献
30.