全文获取类型
收费全文 | 1931篇 |
免费 | 101篇 |
国内免费 | 17篇 |
专业分类
化学 | 1279篇 |
晶体学 | 12篇 |
力学 | 101篇 |
综合类 | 4篇 |
数学 | 306篇 |
物理学 | 347篇 |
出版年
2024年 | 4篇 |
2023年 | 11篇 |
2022年 | 80篇 |
2021年 | 75篇 |
2020年 | 53篇 |
2019年 | 60篇 |
2018年 | 79篇 |
2017年 | 64篇 |
2016年 | 104篇 |
2015年 | 89篇 |
2014年 | 85篇 |
2013年 | 198篇 |
2012年 | 123篇 |
2011年 | 139篇 |
2010年 | 126篇 |
2009年 | 97篇 |
2008年 | 114篇 |
2007年 | 86篇 |
2006年 | 57篇 |
2005年 | 58篇 |
2004年 | 50篇 |
2003年 | 33篇 |
2002年 | 27篇 |
2001年 | 12篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 19篇 |
1996年 | 13篇 |
1995年 | 7篇 |
1993年 | 8篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 12篇 |
1989年 | 4篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 12篇 |
1982年 | 5篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 10篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 12篇 |
1975年 | 8篇 |
1974年 | 4篇 |
1973年 | 5篇 |
1972年 | 4篇 |
1967年 | 3篇 |
排序方式: 共有2049条查询结果,搜索用时 109 毫秒
1.
Kacimi Rachid Bourass Mohamed Toupance Thierry Wazzan Nuha Chemek Mourad El Alamy Aziz Bejjit Lahcen Alimi Kamel Bouachrine Mohammed 《Research on Chemical Intermediates》2020,46(6):3247-3262
Research on Chemical Intermediates - A theoretical study on four organic dyes based on bis(4-hexyloxy)triphenylamine as donor and electron acceptor cyanoacrylic acid with a... 相似文献
2.
A simple, precise and accurate method is proposed for rapid determination of trace amounts of hydroxylamine based on the reaction of hydroxylamine with iodate in acidic media. The reaction of neutral red by the produced nitrite ion was used to monitor the reaction spectrophotometrically at 525 nm by a fixed time method. Hydroxylamine in the range of 0.0400-1.200 microg mL(-1) could be determined. The relative standard deviation for 10 determinations of 0.500 microg mL(-1) hydroxylamine was 1.81% and the limit of detection was 0.010 microg mL(-1). The proposed method was applied to the determination of hydroxylamine in water samples with satisfactory results. 相似文献
3.
Abbas Shockravi Samad Bavili T Esmael Rostami Ali Yousefi Ali Dehjurian Rahim Tohidi 《Journal of inclusion phenomena and macrocyclic chemistry》2004,49(1-2):163-166
Some new dibenzosulfo, dibenzosulfoxo macrocyclic diamides are synthesized. 相似文献
4.
The H-point standard addition method (HPSAM), based on a spectrophotometric measurement for the simultaneous determination of hydrazine and acetylhydrazine, is described. This method is based on the difference between the rates of their reactions with N,N-dimethylaminobenzaldehyde (DAB) in the presence of sodium dodecyl sulfate (SDS) in acidic media. The results showed that hydrazine and acetylhydrazine could be determined simultaneously in the range of 0.020 - 0.70 and 0.20 - 5.0 mg L(-1), respectively. Under the working conditions, the proposed method was successfully applied to the simultaneous determination of hydrazine and acetylhydrazine in several synthetic mixtures and plasma and water samples. 相似文献
5.
Mohamed Hilmy Elnagdi Ramadan Maawad Abdel-Motaleb Mona Mustafa Mohamed Foad Zayed Eman Moustafa Kamel 《Journal of heterocyclic chemistry》1987,24(6):1677-1681
The behaviour of several 2-amino-3-cyano-4H-pyran derivatives toward a variety of nucleophilic reagents is reported. 相似文献
6.
Latifeh Navidpour Leila Karimi Mohsen Amini Mohssen Vosooghi Abbas Shafiee 《Journal of heterocyclic chemistry》2004,41(2):201-204
Arylation of the readily available 3‐alkythio‐5‐aryl‐1,2,4‐triazoles gave 5‐alkylthio‐1,3‐diaryl‐1,2,4‐triazoles in moderate yield. The structures of the latter were confirmed by NOE and 13C‐NMR. 相似文献
7.
In this paper, we prove the Hyers-Ulam-Rassias stability of homomorphisms in quasi-Banach algebras associated to the Pexiderized Cauchy functional equation. This is applied to investigate homomorphisms between quasi-Banach algebras. The concept of Hyers-Ulam-Rassias stability originated from Th.M. Rassias' stability theorem that appeared in his paper [Th.M. Rassias, On the stability of the linear mapping in Banach spaces, Proc. Amer. Math. Soc. 72 (1978) 297-300]. 相似文献
8.
9.
Amir Abbas Matin Ramin Maleki Mir Ali Farajzadeh Khalil Farhadi Reza Hosseinzadeh Abolghasem Jouyban 《Chromatographia》2007,66(5-6):383-387
A new method for extraction and analysis of acetone in human urine based on headspace solid phase microextraction using a
mixture of activated carbon and zeolite as sorbents in a PVC matrix coated on a silver wire and its application to the determination
of ketone bodies is described. Unlike commercial fibers, which are coated on fused silica, the coating adheres strongly to
the silver wire and is thermally stable up to 250 °C. After optimization of coating composition and microextraction conditions
the fiber was used for the analysis of acetone in human urine. 相似文献
10.
In this paper, we apply Adomian decomposition method (shortly, ADM) to develop a fast and accurate algorithm of a special second-order ordinary initial value problems. The ADM does not require discretization and consequently of massive computations. This paper is particularly concerned with the ADM and the results obtained are compared with previously known results using the Quintic C2-spline integration methods. The numerical results demonstrate that the ADM is relatively accurate and easily implemented. 相似文献