全文获取类型
收费全文 | 1007篇 |
免费 | 48篇 |
国内免费 | 241篇 |
专业分类
化学 | 812篇 |
晶体学 | 1篇 |
力学 | 89篇 |
数学 | 64篇 |
物理学 | 330篇 |
出版年
2024年 | 2篇 |
2023年 | 66篇 |
2022年 | 15篇 |
2021年 | 22篇 |
2020年 | 24篇 |
2019年 | 24篇 |
2018年 | 22篇 |
2017年 | 40篇 |
2016年 | 35篇 |
2015年 | 34篇 |
2014年 | 38篇 |
2013年 | 68篇 |
2012年 | 65篇 |
2011年 | 77篇 |
2010年 | 67篇 |
2009年 | 100篇 |
2008年 | 92篇 |
2007年 | 88篇 |
2006年 | 75篇 |
2005年 | 52篇 |
2004年 | 35篇 |
2003年 | 28篇 |
2002年 | 29篇 |
2001年 | 31篇 |
2000年 | 16篇 |
1999年 | 15篇 |
1998年 | 16篇 |
1997年 | 17篇 |
1996年 | 14篇 |
1995年 | 14篇 |
1994年 | 17篇 |
1993年 | 12篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 3篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 7篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1975年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有1296条查询结果,搜索用时 78 毫秒
51.
Hesham Ibrahim Saleh 《中国化学会会志》2002,49(3):341-348
The reactions between strontium and iron nitrates have been studied in an open atmosphere system using three different molar ratios, 1:1 (I), 1:2 (II) and 2:1 (III) at different temperatures as pointed out from the DTA data. The reaction mechanism was discussed based on the chemical composition characterized by means of thermal analysis, X‐ray diffraction patterns, infrared spectra and magnetic susceptibility. It was found that the reaction products depend on both temperature of reaction and the ratio between reactants. The reaction products were found to be composed of a variety of iron compounds that possess different valences: SrFeO2.86, SrFeO2.97, SrFe2O4, SrFe12O19, Sr2Fe2O5 and Sr7Fe10O22 in addition to some accessory reaction products namely α‐Fe2O3 and FeO(OH). 相似文献
52.
V. S. Kushawaha 《光谱学快报》2013,46(10):633-645
An extensive calculation was carried out using the precisely measured value of the Q-band heads and the following molecular constants for the C2π1 2 and the X2σ states, which are responsible for the Green Band System of BaF, were determined. 相似文献
53.
54.
55.
《Comptes Rendus Mecanique》2014,342(10-11):583-594
In this paper we focus on WENO-based methods for the simulation of the 1D Quasi-Relativistic Vlasov–Maxwell (QRVM) model used to describe how a laser wave interacts with and heats a plasma by penetrating into it. We propose several non-oscillatory methods based on either Runge–Kutta (explicit) or Time-Splitting (implicit) time discretizations. We then show preliminary numerical experiments. 相似文献
56.
《Physics letters. A》2020,384(20):126513
An interaction mechanism between graphene and magnetic film in cavity is presented in this work. The pseudospin in graphene can indirectly interact with the spins in magnetic film by the media of a circularly polarized photons under the conditions of high temperature and intense laser field. The interaction energy as well as the average values of pseudospin and spin components are calculated according to a generating functional approach. This interaction mechanism provides a scheme of detecting the pseudospin polarization effect. 相似文献
57.
The hydrogen bonding pattern in complexes of the type [M2+(H2O)6](dmax)2 (M = Mn, Ni, Co, Zn, Cd, Hdmax = 1,3-dimethyl-8-azaxanthine), [M2+(H2O)4(py)2](dmax)2 (M = Mn, Co, Zn, Cd, py = pyridine) and [M2+(dmax)2(H2O)2(py)2]·2H2O (M = Ni, Cu) were studied by ab initio (MP2/LANL2DZ//B3LYP/LANL2DZ) and density functional theory methods (B3LYP/LANL2DZ, B3LYP/6-31G∗∗ and B3PW91/6-31G∗∗). The investigation includes a variety of theoretical analyses, which include interaction energy, many body analyses, electron density analysis, topological analysis, Mulliken atomic charges, natural atomic charges and harmonic vibrational analysis. The geometrical parameters and vibrational frequencies of dmax (the mono anion of 1,3-dimethyl-8-azaxanthine), [M2+(H2O)6] (M = Mn, Ni, Co, Zn, Cd), [M2+(H2O)4·(py)2] (M = Mn, Co, Zn, Cd) and the complexes, calculated by the theoretical methods, were compared with the recent X-ray crystallographic results and it was observed that the results are found to agree well with the crystallographic results. The present calculations provide an important physicochemical insight into metal cations with 1,3-dimethyl-8-azaxanthine. The results also reveal the active role of coordinated water molecules in modulating the binding of the cation through a specific network of hydrogen bonds. The topology of the motifs generated by these hydrogen bonds has been characterized, adapting to the second coordination sphere concepts usually applied to the first (monodentate, chelate, and bridge) coordination sphere. The optimized structures of the Cd2+, Zn2+ and Cu2+ complexes further interact among themselves in a less tight fashion to generate three dimensional structures (a tape-like hydrogen bond network). Finally these tape-like hydrogen bond network were optimized using the B3LYP/LANL2DZ basis set. 相似文献
58.
59.
60.
Interactions between CdTe quantum dots and DNA revealed by capillary electrophoresis with laser‐induced fluorescence detection
下载免费PDF全文
![点击此处可从《Electrophoresis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Maja Stanisavljevic Jana Chomoucka Simona Dostalova Sona Krizkova Marketa Vaculovicova Vojtech Adam Rene Kizek 《Electrophoresis》2014,35(18):2587-2592
Quantum dots (QDs) are one of the most promising nanomaterials, due to their size‐dependent characteristics as well as easily controllable size during the synthesis process. They are promising label material and their interaction with biomolecules is of great interest for science. In this study, CdTe QDs were synthesized under optimal conditions for 2 nm size. Characterization and verification of QDs synthesis procedure were done by fluorimetric method and with CE. Afterwards, QDs interaction with chicken genomic DNA and 500 bpDNA fragment was observed employing CE‐LIF and gel electrophoresis. Performed interaction relies on possible matching between size of QDs and major groove of the DNA, which is approximately 2.1 nm. 相似文献