全文获取类型
收费全文 | 1083篇 |
免费 | 37篇 |
国内免费 | 5篇 |
专业分类
化学 | 728篇 |
晶体学 | 5篇 |
力学 | 46篇 |
数学 | 115篇 |
物理学 | 231篇 |
出版年
2023年 | 10篇 |
2022年 | 16篇 |
2021年 | 21篇 |
2020年 | 24篇 |
2019年 | 22篇 |
2018年 | 16篇 |
2017年 | 18篇 |
2016年 | 26篇 |
2015年 | 22篇 |
2014年 | 17篇 |
2013年 | 52篇 |
2012年 | 77篇 |
2011年 | 81篇 |
2010年 | 29篇 |
2009年 | 29篇 |
2008年 | 44篇 |
2007年 | 62篇 |
2006年 | 39篇 |
2005年 | 53篇 |
2004年 | 43篇 |
2003年 | 31篇 |
2002年 | 17篇 |
2001年 | 13篇 |
2000年 | 20篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1996年 | 7篇 |
1995年 | 9篇 |
1994年 | 9篇 |
1992年 | 7篇 |
1991年 | 10篇 |
1987年 | 7篇 |
1985年 | 13篇 |
1984年 | 10篇 |
1981年 | 9篇 |
1980年 | 8篇 |
1979年 | 9篇 |
1978年 | 10篇 |
1977年 | 11篇 |
1976年 | 12篇 |
1975年 | 11篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1971年 | 6篇 |
1969年 | 8篇 |
1968年 | 10篇 |
1936年 | 6篇 |
1935年 | 6篇 |
1927年 | 9篇 |
1925年 | 6篇 |
排序方式: 共有1125条查询结果,搜索用时 312 毫秒
111.
Jordan G. Brankov 《Journal of statistical physics》1989,56(3-4):309-330
A new analytical technique based on integral transformations with Mittag-Leffler-type kernels is used to derive the finite-size scaling function for the free energy per particle of the mean spherical model with inverse power law asymptotics of the interaction potential. The asymptotic formation of the singularities in the specific heat and magnetic susceptibility at the bulk critical point is studied. 相似文献
112.
Revisiting Stokes' first problem for Maxwell fluids 总被引:1,自引:0,他引:1
Jordan P. M.; Puri Ashok 《The Quarterly Journal of Mechanics and Applied Mathematics》2005,58(2):213-227
113.
114.
Selective reagent ionisation‐time of flight‐mass spectrometry: a rapid technology for the novel analysis of blends of new psychoactive substances
下载免费PDF全文
![点击此处可从《Journal of mass spectrometry : JMS》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Matteo Lanza W. Joe Acton Philipp Sulzer Kostiantyn Breiev Simone Jürschik Alfons Jordan Eugen Hartungen Gernot Hanel Lukas Märk Tilmann D. Märk Chris A. Mayhew 《Journal of mass spectrometry : JMS》2015,50(2):427-431
In this study we demonstrate the potential of selective reagent ionisation‐time of flight‐mass spectrometry for the rapid and selective identification of a popular new psychoactive substance blend called ‘synthacaine’, a mixture that is supposed to imitate the sensory and intoxicating effects of cocaine. Reactions with H3O+ result in protonated parent molecules which can be tentatively assigned to benzocaine and methiopropamine. However, by comparing the product ion branching ratios obtained at two reduced electric field values (90 and 170 Td) for two reagent ions (H3O+ and NO+) to those of the pure chemicals, we show that identification is possible with a much higher level of confidence then when relying solely on the m/z of protonated parent molecules. A rapid and highly selective analytical identification of the constituents of a recreational drug is particularly crucial to medical personnel for the prompt medical treatment of overdoses, toxic effects or allergic reactions. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
115.
Matthew A. Bedics Hayleigh Kearns Jordan M. Cox Sam Mabbott Fatima Ali Neil C. Shand Karen Faulds Jason B. Benedict Duncan Graham Michael R. Detty 《Chemical science》2015,6(4):2302-2306
Surfaced enhanced Raman scattering (SERS) nanotags operating with 1280 nm excitation were constructed from reporter molecules selected from a library of 14 chalcogenopyrylium dyes containing phenyl, 2-thienyl, and 2-selenophenyl substituents and a surface of hollow gold nanoshells (HGNs). These 1280 SERS nanotags are unique as they have multiple chalcogen atoms available which allow them to adsorb strongly onto the gold surface of the HGN thus producing exceptional SERS signals at this long excitation wavelength. Picomolar limits of detection (LOD) were observed and individual reporters of the library were identified by principal component analysis and classified according to their unique structure and SERS spectra. 相似文献
116.
Solvent effects on the intramolecular charge transfer character of N,N-diaryl dihydrophenazine catalysts for organocatalyzed atom transfer radical polymerization
下载免费PDF全文
![点击此处可从《Journal of polymer science. Part A, Polymer chemistry》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Matthew D. Ryan Jordan C. Theriot Chern-Hooi Lim Haishen Yang Andrew G. Lockwood Nathaniel G. Garrison Sarah R. Lincoln Charles B. Musgrave Garret M. Miyake 《Journal of polymer science. Part A, Polymer chemistry》2017,55(18):3017-3027
The nature of intramolecular charge transfer (CT) of N,N-diaryl dihydrophenazine photocatalysts (PCs) in different solvents is explored in context of their performance in organocatalyzed atom transfer radical polymerization (O-ATRP). PCs having a computationally predicted lowest energy excited state exhibiting CT character can operate a highly controlled O-ATRP in a wide range of solvent polarities, from non-polar hexanes to highly polar N,N-dimethylacetamide. For PCs having a computationally predicted lowest energy excited state not possessing CT character, their ability to operate a controlled O-ATRP is decreased. This study confirms the importance of CT character in the excited state for N,N-diaryl dihydrophenazine PCs, and a deeper understanding of the activity of CT PCs has enabled the synthesis of polymers of low dispersity (<1.10) in a controlled fashion. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3017–3027 相似文献
117.
Thomson JW Nagashima K Macdonald PM Ozin GA 《Journal of the American Chemical Society》2011,133(13):5036-5041
In this Article, we present our findings on the formation of metal sulfide nanocrystals from sulfur-alkylamine solutions. By pulsed field gradient diffusion NMR along with the standard toolbox of 1D and 2D NMR, we determined that sulfur-amine solutions used as a sulfur precursor exist as alkylammonium polysulfides at low temperatures. Upon heating to temperatures used in nanocrystal synthesis, the polysulfide ions react with excess amine to generate H(2)S, which combines with the metal precursor to form metal sulfide. Four different reaction pathways were found, each of which produced H(2)S and the byproducts identified in this Article. Thioamides were identified as an intermediate and were shown to exhibit much more rapid kinetics than sulfur-alkylamine solutions at low temperatures in the synthesis of metal sulfide nanocrystals. 相似文献
118.
Francis Jordan 《Topology and its Applications》2011,158(13):1695-1698
Let R denote the real numbers. We construct in ZFC a countable space X such that X has exactly one non-isolated point, X is infraconsonant, and X is not consonant. We conclude that X is a completely regular space such that Isbell topology on C(X,R) is a group topology that coincides with the natural (finest splitting) topology on C(X,R), but the Isbell and compact-open topologies on C(X,R) do not coincide. The example answers two open problems in the literature. 相似文献
119.
120.
The stacking parameters, lattice constants, bond lengths, and bulk moduli of pyrophyllite and montmorillonites (MMTs), with alkali and alkali earth metal ions, are investigated using density functional theory with and without dispersion corrections. For pyrophyllite, it is found that the inclusion of the dispersion corrections significantly improves the agreement of the calculated values of the lattice parameters and bulk modulus with the experimental values. For the MMTs, the calculations predict that the interlayer spacing varies approximately linearly with the cation radius. The inclusion of dispersion corrections leads to sizable shifts of the interlayer spacings to shorter values. In Li-MMT, compaction of the interlayer distance triggers migration of the Li ion into the tetrahedral sheet and close coordination with basal oxygen atoms. Analysis of electron density distributions shows that the isomorphic octahedral Al(3+)/Mg(2+) substitution in MMT causes an increase of electron density on the basal oxygen atoms of the tetrahedral sheets. 相似文献