全文获取类型
收费全文 | 513篇 |
免费 | 20篇 |
国内免费 | 2篇 |
专业分类
化学 | 314篇 |
晶体学 | 3篇 |
力学 | 6篇 |
数学 | 69篇 |
物理学 | 143篇 |
出版年
2018年 | 7篇 |
2017年 | 6篇 |
2016年 | 11篇 |
2015年 | 14篇 |
2014年 | 9篇 |
2013年 | 28篇 |
2012年 | 12篇 |
2011年 | 17篇 |
2010年 | 13篇 |
2009年 | 14篇 |
2008年 | 18篇 |
2007年 | 16篇 |
2006年 | 17篇 |
2005年 | 15篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2001年 | 6篇 |
2000年 | 5篇 |
1999年 | 4篇 |
1998年 | 9篇 |
1997年 | 7篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 4篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 11篇 |
1990年 | 11篇 |
1989年 | 9篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1985年 | 10篇 |
1984年 | 5篇 |
1982年 | 5篇 |
1981年 | 8篇 |
1980年 | 11篇 |
1979年 | 6篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 7篇 |
1975年 | 4篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1969年 | 7篇 |
1968年 | 7篇 |
1967年 | 4篇 |
1966年 | 5篇 |
1960年 | 4篇 |
排序方式: 共有535条查询结果,搜索用时 15 毫秒
461.
462.
The solubility equilibrium of α-GaO(OH) has been investigated at 60°C in solutions of perchloric acid having a constant ionic strength I = 3 m (Na, H)ClO4. The hydrogen ion concentration of the equilibrated solutions was measured with a glass electrode and the concentration of the dissolved GaIII was determined by chelometric titration. The experimental data can be explained by assuming the equilibrium . 相似文献
463.
B. Aengenvoort W. Korten H. Hübel S. Chmel A. Görgen U.J. van Severen W. Pohler R. Zinken T. Härtlein C. Ender F. Köck P. Reiter D. Schwalm F. Schindler J. Gerl R. Schubart F. Azaiez S. Bouneau J. Duprat I. Deloncle 《The European Physical Journal A - Hadrons and Nuclei》1998,1(4):359-364
Three mini-orange conversion–electron spectrometers and four Euroball Ge Cluster detectors have been used for γ–e- coincidence spectroscopy of superdeformed 135Nd. Transitions within the superdeformed band are shown to have the expected E2 multipolarity. The 766.5–keV transition which
links the band to a positive-parity state has a conversion coefficient consistent with M1 multipolarity. Consequently, positive
parity is deduced for the superdeformed band. No evidence for E0 transitions was found.
Received: 22 December 1997 / Revised version: 19 January 1998 相似文献
464.
Hansgeorg Schindler 《Fresenius' Journal of Analytical Chemistry》1984,317(6):625-626
465.
Baltrusaitis RM Becker JJ Blaylock GT Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dado S Dorfan DE Dubois GP Duncan AL Einsweiler KF Eisenstein BI Fabrizio R Gladding G Grancagnolo F Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Lockman WS Mallik U Mockett PM Mozley RF Nappi A Odian A Partridge R Perrier J Plaetzer SA Richman JD Roehrig JR Russell JJ Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C Sleeman JC Spadafora AL Stockdale IE 《Physical review letters》1985,55(18):1842-1845
466.
Pai RK Hild S Ziegler A Marti O 《Langmuir : the ACS journal of surfaces and colloids》2004,20(8):3123-3128
The structure of the polymeric substrate plays an important role in the nucleation of calcium carbonate crystals. In this study a synthetic water-soluble poly(acrylamide-co-2-acrylamido-2-methyl-1-propane sodium sufonate-co-n-vinyl pyrrolidone) was found to be a substrate favoring the nucleation of polymorphs of calcium carbonate crystals under specific experimental conditions. Morphological characterization of the polymorphs was done using atomic force microscopy, scanning electron microscopy, energy dispersive spectroscopy, FTIR analysis, and X-ray diffraction. If calcium carbonate is precipitated in the presence of terpolymer, a remarkable increase in nucleation density (number of crystals per unit area) was observed. Stacked crystals of rhombohedral morphology that formed may be due to the presence of sodium sulfonate groups on the terpolymer. However, in the presence of poly-L-aspartic acid, almost all crystals are hollow and have needlelike or plate like morphology was formed. This change in calcium carbonate morphology can be explained by the variation of the polymer conformation, if poly- L-aspartic acid is present. 相似文献
467.
Becker JJ Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Dorfan DE Dubois GP Duncan AL Eigen G Einsweiler KF Eisenstein BI Freese T Gladding G Grancagnolo F Grab C Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Li A Lockman WS Mallik U Matthews CG Mockett PM Mozley RF Nemati B Odian A Partridge R Perrier J Pitman D Plaetzer SA Richman JD Sadrozinski HF Scarlatella M Schalk TL Schindler RH Seiden A Simopoulos C Spadafora AL Stockdale IE Stockhausen W 《Physical review letters》1987,59(2):186-189
468.
Baltrusaitis RM Becker JJ Blaylock GT Bolton T Brown JS Bunnell KO Burnett TH Cassell RE Coffman D Cook V Coward DH Cui H Dado S Del Papa C Dorfan DE Dubois GP Duncan AL Eigen G Einsweiler KF Eisenstein BI Fabrizio R Favart D Gladding G Grancagnolo F Guy AD Hamilton RP Hauser J Heusch CA Hitlin DG Köpke L Lockman WS Mallik U Matthews CG Mockett PM Moss L Mozley RF Nappi A Nemati B Odian A Partridge R Perrier J Plaetzer SA Richman JD Roehrig J Russell JJ Sadrozinski HF Scarlatella M Schalk TL 《Physical review letters》1986,56(2):107-110
469.
T. Benter M. Liesner V. Sauerland R. N. Schindler 《Fresenius' Journal of Analytical Chemistry》1995,351(6):489-492
One- and two-colour photoionisation spectra for NO2 have been investigated using a time of flight mass spectrometer as detector to find the most efficient REMPI process for analytical applications. Two different inlet systems have been employed: a pulsed supersonic jet expansion stage and a flow reactor. Selective and sensitive mass spectrometric determinations of free NO2 have been possible even in the presence of high concentrations of organic nitrates, HNO3 and other NO2 precursors. Employing two-colour (1+1+1) excitation using a concentration of HNO35·1014 molecules/cm3 a detection limit of 5·1011 molecules/cm3 has been found for NO2 whereas in the absence of HNO3 a detection limit of 5·1010 molecules/cm3 is reported. 相似文献
470.
Börzel H Comba P Hagen KS Kerscher M Pritzkow H Schatz M Schindler S Walter O 《Inorganic chemistry》2002,41(21):5440-5452
Copper(I) and copper(II) complexes of two mononucleating and four dinucleating tetradentate ligands with a bispidine backbone (2,4-substituted (2-pyridyl or 4-methyl-2-pyridyl) 3,7-diazabicyclo[3.3.1]nonanone) have been prepared and analyzed structurally, spectroscopically, and electrochemically. The structures of the copper chromophores are square pyramidal, except for two copper(I) compounds which are four-coordinate with one noncoordinated pyridine. The other copper(I) structures have the two pyridine donors, the co-ligand (NCCH(3)), and one of the tertiary amines (N3) in-plane with the copper center and the other amine (N7) coordinated axially (Cu-N3 > Cu-N7, approximately 2.25 A vs 2.20 A). The copper(II) compounds with pyridine donors have a similar structure, but the axial amine has a weaker bond to the copper(II) center (Cu-N3 < Cu-N7, approximately 2.03 A vs 2.30 A). The structures with methylated pyridine donors are also square pyramidal with the co-ligands (Cl(-) or NCCH(3)) in-plane. With NCCH(3) the same structural type as for the other copper(II) complexes is observed, and with the bulkier Cl(-) the co-ligand is trans to N7, leading to a square pyramidal structure with the pyridine donors rotated out of the basal plane and only a small difference between axial and in-plane amines (2.15, 2.12 A). These structural differences, enforced by the rigid bispidine backbone, lead to large variations in spectroscopic and electrochemical properties and reactivities. Oxygenation of the copper(I) complexes with pyridine-substituted bispidine ligands leads to relatively stable mu-peroxo-dicopper(II) complexes; with a preorganization of the dicopper chromophores, by linking the two donor sets, these peroxo compounds are stable at room temperature for up to 1 h. The stabilization of the peroxo complexes is to a large extent attributed to the square pyramidal coordination geometry with the substrate bound in the basal plane, a structural motif enforced by the rigid bispidine backbone. The stabilities and structural properties are also seen to correlate with the spectroscopic (UV-vis and Raman) and electrochemical properties. 相似文献