全文获取类型
收费全文 | 152篇 |
免费 | 8篇 |
专业分类
化学 | 119篇 |
力学 | 1篇 |
数学 | 3篇 |
物理学 | 37篇 |
出版年
2023年 | 1篇 |
2021年 | 2篇 |
2020年 | 7篇 |
2019年 | 3篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2014年 | 7篇 |
2013年 | 11篇 |
2012年 | 7篇 |
2011年 | 11篇 |
2010年 | 15篇 |
2009年 | 7篇 |
2008年 | 9篇 |
2007年 | 4篇 |
2006年 | 8篇 |
2005年 | 13篇 |
2004年 | 12篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2000年 | 4篇 |
1998年 | 1篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 453 毫秒
1.
Dr. George Dhimba Prof. Dr. Alfred Muller Prof. Dr. Koop Lammertsma 《欧洲无机化学杂志》2023,26(25):e202300256
Cis-MoO2(nacnac)2 (nacnac=β-diketiminate) can be a viable chiral-at-metal catalyst when its two β-diketiminate (nacnac) ligands are N-substituted to prevent Λ⇌Δ racemization. Even simple methyl groups raise the barriers for racemization significantly for the Bailar, Rây-Dutt, Conte-Hippler, and Dhimba-Muller-Lammertsma (DML) twists to a respectable 28.5, 37.8, 30.5, and 25.1 kcal/mol, respectively, at ωB97X-D/6-311+G(2d,p) (LANL2DZ for Mo) including acetonitrile solvation. The lowest energy DML barrier increases to ΔGo=27.4 kcal/mol with N-substituted t-butyl groups. The nacnac ligands’ electronic and steric components to the racemization barriers are discussed. 相似文献
2.
Koop I. A. Milstein A. I. Nikolaev N. N. Popov A. S. Salnikov S. G. Shatunov P. Yu. Shatunov Yu. M. 《Physics of Particles and Nuclei Letters》2020,17(2):154-159
Physics of Particles and Nuclei Letters - Possible approaches to experimentally detecting P-parity violation in polarized proton or deuteron interactions with an unpolarized target are discussed.... 相似文献
3.
4.
Mokgolela M. Mogorosi John R. Moss Selwyn F. Mapolie Koop Lammertsma 《Journal of organometallic chemistry》2011,696(23):3585-3592
New N-functionalised 2-phosphinobenzaldimino (P^N) ligands bearing 3-picolyl, furfuryl, thiophene-2-methyl, thiophene-2-ethyl, and benzyl groups have been prepared in good yield. The 2-phosphinobenzaldimino ligands were reacted with PdCl2(COD) to give the corresponding metal complexes of the type Pd(L)Cl2 (L = 2-phosphinobenzaldimino (P^N) ligand). All compounds were fully characterized using spectroscopic and analytical techniques, including 1H, 13C, and 31P NMR and IR spectroscopies, mass spectrometry and elemental analysis. Selected neutral palladium complexes were evaluated as catalyst precursors in ethylene oligomerisation reactions, after activation with a co-catalyst (MMAO, EtAlCl2, or Et2AlCl). 相似文献
5.
Facile Synthesis of Phosphaamidines and Phosphaamidinates using Nitrilium Ions as an Imine Synthon 下载免费PDF全文
Tom van Dijk Dr. Sebastian Burck Mark K. Rong Amos J. Rosenthal Dr. Martin Nieger Dr. J. Chris Slootweg Prof. Dr. Koop Lammertsma 《Angewandte Chemie (International ed. in English)》2014,53(34):9068-9071
Readily accessible nitrilium triflates are convenient imine building blocks for the expedient synthesis of a novel class of 1,3‐P,N ligands as demonstrated for the reaction with primary phosphanes. This procedure allows variation of all substituents. X‐ray crystal structures are reported for nitrilium ions, phosphaamidines, and three phosphaamidinate complexes. The lithium phosphaamidinate is N coordinated and its reaction with [AuCl(tht)] (tht=tetrahydrothiophene) gives a unique P‐bridged gold trimer, while a P,N‐bidentate complex results from [{RhCl(cod)}2]. The nitrilium ion methodology allows extension of the 1,3‐P,N motive to bis(imino)phosphanes, which are the neutral phosphorus analogues of the valuable β‐diketiminate ligand. 相似文献
6.
D. E. Berkaev D. B. Shwartz P. Yu. Shatunov Yu. A. Rogovskii A. L. Romanov I. A. Koop Yu. M. Shatunov I. M. Zemlyanskii A. P. Lysenko E. A. Perevedentsev A. S. Stankevich A. I. Senchenko B. I. Khazin A. V. Anisenkov S. E. Gayazov A. N. Kozyrev A. E. Ryzhenenkov D. N. Shemyakin L. B. Epshtein S. I. Serednyakov P. M. Astigeevich D. P. Kovrizhin K. A. Martin A. E. Obrazovskii I. K. Surin L. V. Kardapoltsev O. V. Belikov K. M. Gorchakov A. N. Kirpotin A. N. Skrinskii 《Journal of Experimental and Theoretical Physics》2011,113(2):213-220
In 2007, at the Institute of Nuclear Physics (Novosibirsk), the construction of the VEPP-2000 electron-positron collider was completed. The first electron beam was injected into the accelerator structure with turned-off solenoids of the final focus. This mode was used to tune all subsystems of the facility and to train the vacuum chamber using synchrotron radiation at electron currents of up to 150 mA. The VEPP-2000 structure with small beta functions and partially turned-on solenoids was used for the first testing of the “round beams” scheme at an energy of 508 MeV. Beam-beam effects were studied in strong-weak and strong-strong modes. Measurements of the beam sizes in both cases showed a dependence corresponding to model predictions for round colliding beams. Using a modernized SND (spherical neutral detector), the first energy calibration of the VEPP-2000 collider was performed by measuring the excitation curve of the phimeson resonance; the phi-meson mass is known with high accuracy from previous experiments at VEEP-2M. In October 2009, a KMD-3 (cryogenic magnetic detector) was installed at the VEPP-2000 facility, and the physics program with both the SND and LMD-3 particle detectors was started in the energy range of 1–1.9 GeV. This first experimental season was completed in summer 2010 with precision energy calibration by resonant depolarization. 相似文献
7.
Sebastian Burck Dr. Sander G. A. van Assema Dr. Bas Lastdrager Dr. J. Chris Slootweg Dr. Andreas W. Ehlers Dr. José M. Otero Dr. Bruno Dacunha‐Marinho Dr. Antonio L. Llamas‐Saiz Dr. Mark Overhand Dr. Mark J. van Raaij Dr. Koop Lammertsma Prof. Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(33):8134-8145
The natural product Gramicidin S is a promising scaffold for novel oligopeptide‐based bisphosphine ligands, combining the advantageous rigid chiral backbone with the close proximity of phosphine substituents. The required unnatural, phosphine‐containing, amino acid building blocks were synthesized by means of a novel protocol that involves the enantioselective alkylation of a chiral nickel Schiff base template. Three Ni complexes were prepared with different alkyl chains between the phosphine group and the α‐carbon atom of the incorporated glycine; the absolute stereochemistry of two of them was determined by single‐crystal X‐ray structure analysis. By detaching the template, enantiopure L ‐phosphine amino acids resulted enabling the solid‐phase, stepwise construction of a linear sequence of the phosphine‐modified oligopeptides. On cyclization three bisphosphine‐substituted Gramicidin S analogues resulted, differing only in the size and shape of the linkage between the phosphine groups and the oligopeptides backbone. Their crystal structures suggest these species to have potential as chelating ligands. 相似文献
8.
9.
V. L. Ivanov R. R. Akhmetshin A. N. Amirkhanov A. V. Anisenkov V. M. Aulchenko V. S. Banzarov N. S. Bashtovoy D. E. Berkaev A. V. Bragin S. I. Eidelman D. A. Epifanov L. B. Epshteyn A. L. Erofeev G. V. Fedotovich S. E. Gayazov A. A. Grebenuk D. N. Grigoriev E. M. Gromov F. V. Ignatov S. V. Karpov V. F. Kazanin B. I. Khazin I. A. Koop O. A. Kovalenko A. N. Kozyrev E. A. Kozyrev P. P. Krokovny A. E. Kuzmenko A. S. Kuzmin I. B. Logashenko P. A. Lukin K. Yu. Mikhailov V. S. Okhapkin Yu. N. Pestov E. A. Perevedentsev A. S. Popov G. P. Razuvaev Yu. A. Rogovsky A. L. Romanov A. A. Ruban N. M. Ryskulov A. E. Ryzhenenkov V. E. Shebalin D. N. Shemyakin B. A. Shwartz D. B. Shwartz A. L. Sibidanov Yu. M. Shatunov P. Yu. Shatunov E. P. Solodov V. M. Titov A. A. Talyshev A. I. Vorobiov Yu. V. Yudin 《Physics of Atomic Nuclei》2016,79(2):251-259
We report preliminary results on the cross section of the process e+e? → φ(1020)η measured at 30 center-of-mass energy points in the range from 1.59 up to 2.0 GeV. Data analysis is based on the integrated luminosity of 22 pb?1 collected with the CMD-3 detector in 2011–2012. The obtained cross section agrees with the BaBar measurement and has better statistical accuracy. 相似文献
10.