全文获取类型
收费全文 | 387篇 |
免费 | 53篇 |
国内免费 | 1篇 |
专业分类
化学 | 381篇 |
力学 | 6篇 |
数学 | 30篇 |
物理学 | 24篇 |
出版年
2024年 | 3篇 |
2023年 | 13篇 |
2022年 | 14篇 |
2021年 | 18篇 |
2020年 | 31篇 |
2019年 | 31篇 |
2018年 | 10篇 |
2017年 | 9篇 |
2016年 | 31篇 |
2015年 | 29篇 |
2014年 | 33篇 |
2013年 | 23篇 |
2012年 | 41篇 |
2011年 | 37篇 |
2010年 | 19篇 |
2009年 | 9篇 |
2008年 | 22篇 |
2007年 | 19篇 |
2006年 | 12篇 |
2005年 | 9篇 |
2004年 | 5篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 6篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1987年 | 1篇 |
1985年 | 1篇 |
1982年 | 1篇 |
1973年 | 1篇 |
1943年 | 1篇 |
排序方式: 共有441条查询结果,搜索用时 31 毫秒
151.
152.
Oxide nanomaterials: synthetic developments, mechanistic studies, and technological innovations 总被引:1,自引:0,他引:1
Patzke GR Zhou Y Kontic R Conrad F 《Angewandte Chemie (International ed. in English)》2011,50(4):826-859
Oxide nanomaterials are indispensable for nanotechnological innovations, because they combine an infinite variety of structural motifs and properties with manifold morphological features. Given that new oxide materials are almost reported on a daily basis, considerable synthetic and technological work remains to be done to fully exploit this ever increasing family of compounds for innovative nano-applications. This calls for reliable and scalable preparative approaches to oxide nanomaterials and their development remains a challenge for many complex nanostructured oxides. Oxide nanomaterials with special physicochemical features and unusual morphologies are still difficult to access by classic synthetic pathways. The limitless options for creating nano-oxide building blocks open up new technological perspectives with the potential to revolutionize areas ranging from data processing to biocatalysis. Oxide nanotechnology of the 21st century thus needs a strong interplay of preparative creativity, analytical skills, and new ideas for synergistic implementations. 相似文献
153.
Brügger G Frey HM Steinegger P Balmer F Leutwyler S 《The journal of physical chemistry. A》2011,115(34):9567-9578
We combine femtosecond time-resolved rotational coherence spectroscopy with high-level ab initio theory to obtain accurate structural information for the nonpolar molecules cyclohexane (C(6)H(12)) and cyclohexane-d(12) (C(6)D(12)). We measured the rotational B(0) and centrifugal distortion constants D(J), D(JK) of the v = 0 states of C(6)H(12) and C(6)D(12) to high accuracy, for example, B(0)(C(6)H(12)) = 4306.08(5) MHz, as well as B(v) for the vibrationally excited states ν(32), ν(6), ν(16) and ν(24) of C(6)H(12) and additionally ν(15) for C(6)D(12). To successfully reproduce the experimental RCS transient, the overtone and combination levels 2ν(32), 3ν(32), ν(32) + ν(6), and ν(32) + ν(16) had to be included in the RCS model calculations. The experimental rotational constants are compared to those obtained at the second-order M?ller-Plesset (MP2) level. Combining the experimental and calculated rotational constants with the calculated equilibrium bond lengths and angles allows determination of accurate semiexperimental equilibrium structure parameters, for example, r(e)(C-C) = 1.526 ± 0.001 ?, r(e)(C-H(axial)) = 1.098 ± 0.001 ?, and r(e)(C-H(equatorial)) = 1.093 ± 0.001 ?. The equilibrium C-C bond length of C(6)H(12) is only 0.004 ? longer than that of ethane. The effect of ring strain due to the unfavorable gauche interactions is mainly manifested as small deviations from the C-C-C, C-C-H(axial), and C-C-H(equatorial) angles from the tetrahedral value. 相似文献
154.
Joseph V Schulte F Rooch H Feldmann I Dörfel I Österle W Panne U Kneipp J 《Chemical communications (Cambridge, England)》2011,47(11):3236-3238
Silver nanoparticles were generated based on citrate reduction in the ultrastructure of the sporopollenin biopolymer of Ambrosia artemisiifolia (ragweed) and Secale cereale (rye). The nanoparticles enable the acquisition of SERS spectra and thereby a vibrational characterization of the local molecular structure of sporopollenin. 相似文献
155.
Jayamurugan G Gisselbrecht JP Boudon C Schoenebeck F Schweizer WB Bernet B Diederich F 《Chemical communications (Cambridge, England)》2011,47(15):4520-4522
Non-concerted [2+2] and [4+2] cycloadditions between N,N-dimethylanilino-substituted 1,1,2,4,4-pentacyanobuta-1,3-diene and 4-ethynyl-N,N-dimethylaniline are controlled by solvent polarity and provide access to a highly functionalised 6,6-dicyanopentafulvene featuring an intense, low-energy charge-transfer band and to an unusual spirocyclic zwitterion, characterised by X-ray analysis. 相似文献
156.
F Heinemann V Betaneli FA Thomas P Schwille 《Langmuir : the ACS journal of surfaces and colloids》2012,28(37):13395-13404
Fluorescence correlation spectroscopy (FCS) measurements are widely used for determination of diffusion coefficients of lipids and proteins in biological membranes. In recent years, several variants of FCS have been introduced. However, a comprehensive comparison of these methods on identical systems has so far been lacking. In addition, there exist no consistent values of already determined diffusion coefficients for well-known or widely used membrane systems. This study aims to contribute to a better comparability of FCS experiments on membranes by determining the absolute diffusion coefficient of the fluorescent lipid analog 1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine (DiD) in giant unilamellar vesicles (GUVs) made of dioleoylphosphatidylcholine (DOPC), which can in future studies be used as a reference value. For this purpose, five FCS variants, employing different calibration methods, were compared. Potential error sources for each particular FCS method and strategies to avoid them are discussed. The obtained absolute diffusion coefficients for DiD in DOPC were in good agreement for all investigated FCS variants. An average diffusion coefficient of D = 10.0 ± 0.4 μm(2) s(-1) at 23.5 ± 1.5 °C was obtained. The independent confirmation with different methods indicates that this value can be safely used for calibration purposes. Moreover, the comparability of the methods also in the case of slow diffusion was verified by measuring diffusion coefficients of DiD in GUVs consisting of DOPC and cholesterol. 相似文献
157.
158.
Schlegel MC Sarfraz A Müller U Panne U Emmerling F 《Angewandte Chemie (International ed. in English)》2012,51(20):4993-4996
Setting cement: highly dynamic hydration processes that occur during the first seconds of cement hydration were studied by time-resolved synchrotron X-ray diffraction. Polycarboxylate ether additives were found to influence the formation of the initial crystalline hydration products on a molecular level. 相似文献
159.
160.