全文获取类型
收费全文 | 1797篇 |
免费 | 39篇 |
国内免费 | 5篇 |
专业分类
化学 | 1325篇 |
晶体学 | 3篇 |
力学 | 32篇 |
数学 | 264篇 |
物理学 | 217篇 |
出版年
2022年 | 16篇 |
2021年 | 23篇 |
2020年 | 36篇 |
2019年 | 29篇 |
2018年 | 14篇 |
2017年 | 14篇 |
2016年 | 26篇 |
2015年 | 41篇 |
2014年 | 44篇 |
2013年 | 70篇 |
2012年 | 80篇 |
2011年 | 98篇 |
2010年 | 56篇 |
2009年 | 63篇 |
2008年 | 82篇 |
2007年 | 71篇 |
2006年 | 65篇 |
2005年 | 58篇 |
2004年 | 70篇 |
2003年 | 57篇 |
2002年 | 62篇 |
2001年 | 34篇 |
2000年 | 22篇 |
1999年 | 25篇 |
1998年 | 17篇 |
1997年 | 37篇 |
1996年 | 28篇 |
1995年 | 12篇 |
1993年 | 19篇 |
1992年 | 19篇 |
1991年 | 14篇 |
1990年 | 18篇 |
1989年 | 28篇 |
1988年 | 19篇 |
1987年 | 26篇 |
1986年 | 24篇 |
1985年 | 32篇 |
1984年 | 23篇 |
1983年 | 20篇 |
1982年 | 25篇 |
1981年 | 18篇 |
1979年 | 26篇 |
1978年 | 26篇 |
1977年 | 28篇 |
1976年 | 35篇 |
1975年 | 17篇 |
1974年 | 17篇 |
1973年 | 24篇 |
1972年 | 16篇 |
1970年 | 13篇 |
排序方式: 共有1841条查询结果,搜索用时 15 毫秒
81.
Hubert Grudzński 《Reports on Mathematical Physics》2004,53(3):331-338
New elements of the dual cone of the set of fermion N-representable 2-density operators are proposed. So far, the explicit form of the corresponding necessary conditions for N-representability is obtained for N = 3. In this case the new condition is stronger than the known B- and C-conditions for 3-representability. The results provide evidence that in the spectral decomposition of the N-representable 2-density operator there exists an intrinsic relation between the eigenvalue and the corresponding eigenfunction. 相似文献
82.
83.
F. A. Beck J. Dudek B. Haas J. C. Merdinger A. Nourreddine Y. Schutz J. P. Vivien Ph Hubert D. Dassié G. Bastin L. Nguyen J. P. Thibaud W. Nazarewicz 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(2):119-132
High spin states in the nucleus154Er have been reinvestigated using the123Sb(35Cl, 4n) reaction and a variety of spectroscopic techniques including excitation functions,γ-γ coincidences,γ angular distribution and linear polarization measurements. From the measured energies, relative intensities and transition multipolarities a new level scheme has been deduced up to an excitation energy of ~12 MeV and spin 36. An interpretation of the experimental results is given in terms of the deformed Woods-Saxon orbitals. Gigantic backbending (superdeformation) effect is studied theoretically within the cranking model. 相似文献
84.
B. Blank J. -J. Gaimard H. Geissel K. -H. Schmidt H. Stelzer K. Sümmerer D. Bazin R. Del Moral J. P. Dufour A. Fleury F. Hubert H. -G. Clerc M. Steiner 《Zeitschrift für Physik A Hadrons and Nuclei》1992,343(4):375-379
Total charge-changing cross sections have been measured for8Li on C and Pb targets, for9Li on C, Al, Cu, Sn and Pb targets, as well as for11Li on C, Sn and Pb targets at about 80 MeV/nucleon. These data are compared to measured total reaction cross sections and Glauber-type calculations using Hartree-Fock density distributions. These comparisons allow to draw conclusions on the proton density distribution of the neutronrich lithium isotopes. The results show that even for the most exotic nucleus11Li the proton distribution is only very weakly influenced by the long tail in the neutron density distribution already established in several experiments. 相似文献
85.
In a systematic study of the transfer process to sulphur dioxide, in seven different H2 + SO2 gas mixtures, the time spectra of the muonic sulphur X-rays yield muon transfer rates to the SO2 molecule, deduced from the lifetimes of the p atoms, which agree all well with each other. The muonic oxygen time spectra show an additional structure as if p atoms of another kind were present. Reduced transfer ratesO are reproducible if one uses the model of ephemeral p atoms. The intensity ratios between the different kinds of p atoms are also discussed in the framework of this model and the one of black and white p atoms. 相似文献
86.
Daniel S. Covita Dimitrios F. Anagnostopoulos Hermann Fuhrmann Hubert Gorke Detlev Gotta Alexander Gruber Albert Hirtl Tomoichi Ishiwatari Paul Indelicato Thomas S. Jensen Eric-Olivier Le Bigot Valeri E. Markushin Michael Nekipelov Vladimir N. Pomerantsev Vladimir P. Popov Joaquim M. F. dos Santos Philipp Schmid Leopold M. Simons Marian Theisen Martino Trassinelli Joao F. C. A. Veloso Johann Zmeskal 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2018,72(4):72
87.
Dr. Yanhui Wang Dr. Sanghoon Kim Dr. Nicolas Louvain Dr. Johan G. Alauzun Dr. P. Hubert Mutin 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(18):4767-4774
An original, halide-free non-hydrolytic sol–gel route to mesoporous anatase TiO2 with hierarchical porosity and high specific surface area is reported. This route is based on the reaction at 200 °C of titanium(IV) isopropoxide with acetic anhydride, in the absence of a catalyst or solvent. NMR spectroscopic studies indicate that this method provides an efficient, truly non-hydrolytic and aprotic route to TiO2. Formation of the oxide involves successive acetoxylation and condensation reactions, both with ester elimination. The resulting TiO2 materials were nanocrystalline, even before calcination. Small (about 10 nm) anatase nanocrystals spontaneously aggregated to form mesoporous micron-sized particles with high specific surface area (240 m2 g−1 before calcination). Evaluation of the lithium storage performances shows a high reversible specific capacity, particularly for the non-calcined sample with the highest specific surface area favouring pseudo-capacitive storage: 253 mAh g−1 at 0.1 C and 218 mAh g−1 at 1 C (C=336 mA g−1). This sample also shows good cyclability (92 % retention after 200 cycles at 336 mA g−1) with a high coulombic efficiency (99.8 %). Synthesis in the presence of a solvent (toluene or squalane) offers the possibility to tune the morphology and texture of the TiO2 nanomaterials. 相似文献
88.
Dr. Markus Hiller Thomas Sittel Prof. Dr. Hubert Wadepohl Prof. Dr. Markus Enders 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(45):10668-10677
Combination of three radical anionic Ph-BIAN ligands (Ph-BIAN=bis-(phenylimino)-acenaphthenequinone) with lanthanoid ions leads to a series of homoleptic, six-coordinate complexes of the type Ln(Ph-BIAN)3. Magnetic coupling data were measured by paramagnetic solution NMR spectroscopy. Combining 1H NMR with 2H NMR of partially deuterated compounds allowed a detailed study of the magnetic susceptibility anisotropies over a large temperature range. The observed chemical shifts were separated into ligand- and metal-centered contributions by comparison with the Y analogue (diamagnetic at the metal). The metal-centered contributions of the complexes with the paramagnetic ions could then be separated into pseudocontact and Fermi contact shifts. The latter is large within the Ph-BIAN scaffold, which shows that magnetic coupling is significant between the lanthanide ion and the radical ligand. Pseudocontact shifts were further correlated to structural data obtained from X-ray diffraction experiments. Ligand-field parameters were determined by fitting the temperature dependence of the observed magnetic susceptibility anisotropies. The electronic structure determined by this approach shows, that the Er and Tm analogues are candidates for single molecule magnets (SMM). These results demonstrate the possibilities for the application of NMR spectroscopy in investigations of paramagnetic systems in general and single molecule magnets in particular. 相似文献
89.
90.