全文获取类型
收费全文 | 724篇 |
免费 | 40篇 |
国内免费 | 4篇 |
专业分类
化学 | 532篇 |
晶体学 | 5篇 |
力学 | 9篇 |
数学 | 33篇 |
物理学 | 189篇 |
出版年
2023年 | 7篇 |
2022年 | 4篇 |
2021年 | 9篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 18篇 |
2017年 | 8篇 |
2016年 | 27篇 |
2015年 | 16篇 |
2014年 | 28篇 |
2013年 | 27篇 |
2012年 | 48篇 |
2011年 | 45篇 |
2010年 | 29篇 |
2009年 | 24篇 |
2008年 | 31篇 |
2007年 | 26篇 |
2006年 | 26篇 |
2005年 | 28篇 |
2004年 | 30篇 |
2003年 | 16篇 |
2002年 | 22篇 |
2001年 | 26篇 |
2000年 | 17篇 |
1999年 | 11篇 |
1998年 | 3篇 |
1997年 | 17篇 |
1996年 | 9篇 |
1995年 | 4篇 |
1994年 | 22篇 |
1993年 | 8篇 |
1992年 | 7篇 |
1991年 | 9篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 6篇 |
1987年 | 4篇 |
1986年 | 11篇 |
1985年 | 8篇 |
1984年 | 15篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 14篇 |
1977年 | 7篇 |
1976年 | 11篇 |
1974年 | 2篇 |
1973年 | 6篇 |
1971年 | 2篇 |
排序方式: 共有768条查询结果,搜索用时 31 毫秒
71.
72.
Hirotaka Inoda Taihei Nishiyama Takashi Yoshikado Yusuke Suwanai Tomofumi Santa 《Biomedical chromatography : BMC》2011,25(6):635-640
The derivatization reagents for carboxylic acids, N‐(Pyridin‐3‐yl)hydrazinecarbothioamide, N‐[4‐(dimethylamino)phenyl]hydrazinecarbothioamide, 1‐(2‐aminoethyl)‐3‐(pyridin‐3‐yl)thiourea, 1‐(2‐aminoethyl)‐3‐[4‐(dimethylamino)phenyl]thiourea and 4‐(2‐aminoethyl)‐N‐phenylpiperazine‐1‐carbothioamide were synthesized. These reagents reacted with carboxylic acids at 60°C for 45 min in the presence of the condensation reagents. The generated derivatives were favorably separated on the reversed‐phase column and sensitively detected by electrospray ionization tandem mass spectrometry. These reagents enhanced the electrospray ionization response of the analyte and generated a particular product ion efficiently by collision‐induced dissociation, and thus they were suitable for MS/MS detection. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
73.
74.
75.
76.
G. M. Kalvius L. Asch D. R. Noakes R. Keitel J. H. Brewer E. J. Ansaldo F. J. Litterst B. Boucher J. Chappert A. Yaouanc T. Yamazaki K. Nagamine K. Nishiyama O. Hartmann R. Wäppling 《Hyperfine Interactions》1986,31(1-4):303-308
Crystalline (cr-) Dyag [CsC] structure] orders antiferro-magnetically with TN≅60K; amorphous (am-) DyAg ferro-magnetically with TC≈-18K. We measured the longitudinal field (LF) μ+SR relaxation functions GZZ(t) for 5K<T<300K using surface muons. In the paramagnetic state. cr-DyAg gives an exponential GZZ (t) in the relaxation rate rising first slowly then more rapidlynear TN; no decoupling is observed in LF up to 0.4T. In the ordered state we see a Lorentzian Kubo-Toyabe GZZ(t), becoming nearly static at the lowest temperatures. Its static width is very narrow (Δ≈-7 MHz), and full dceoupling is
achieved here in 0.1 T. On approaching TN, the fluctuation rate and the static width increase mootonically bt the field distribution remains Loratzian. A LF of 0.4T
is then insufficient to quench the fast exponential relaxation. In paramagnetic am-DyAg, the μ+ depolarization is always much faster then in cr-DyAg. At lower temperatures it is better described by a root-exponential
than an exponential GZZ(t). Below TC an exponentially relaxing signal with 1/3 amplitude is seen. The decoupling effect of LF up to 0.4T was negligible at all
temperatures. 相似文献
77.
T. Kondow A. Matsushita K. Kuchitsu K. Nishiyama Y. Morozumi K. Nagamine 《Hyperfine Interactions》1986,32(1-4):807-812
Surface muons produced in UT-MSL were introduced into argon gas of 4.0±0.2 atm with NO2 (0–30 ppm), and muonium signals were detected in the presence of a transverse (1.7–3.4 G) and a longitudinal magnetic field
(0–3.5 kG) at 295±1 K. The cross section for the transverse relaxation was (11.0±1.0)×10−16 cm2. The relaxation rates in different longitudinal magnetic fields show that the rate does not follow the conventional equation
which assumes that the relaxation occurs mainly by spin-exchange interaction. Similar measurements were performed for the
Mu+O2 system. These findings indicate that chemical reactions contribute to these relaxation rates. 相似文献
78.
Y. Todate N. Ohnishi M. Tanaka K. Nishiyama K. Nagamine 《Hyperfine Interactions》1997,104(1-4):375-380
Zero and longitudinal field μSR measurements on diluted triangular‐lattice antiferromagnet LuFeMgO4 have revealed gradual and highly anisotropic slowing‐down of spin fluctuation. Relaxation rate \lambda in the condition with
initial muon spins perpendicular to the hexagonal c‐plane shows divergent behavior while that in the parallel configuration
remains finite. At certain temperature range the fluctuation of spins is suppressed by a small external magnetic field. Monte
Carlo calculation suggests that the correlation time for z(c)‐component of spins diverges first on cooling.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
79.
The uniaxial pressure dependence of the muonium hyperfine tensor was measured at 80 K. Uniaxial pressures (0 and 0.2 GPa)
were applied along the a‐axis of quartz, and the hyperfine tensor was measured by applying various transverse fields between
0 and 7 G. The structure appears to be the result of the three chemically equivalent sites in quartz. When pressure is applied
perpendicular to the crystallographic c‐axis of quartz, the symmetry of these sites is broken such that two chemically inequivalent
sites are observed. The resulting hyperfine structure is discussed and qualitative explanations are proposed.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
80.
Salt‐Free Reduction of Nonprecious Transition‐Metal Compounds: Generation of Amorphous Ni Nanoparticles for Catalytic C–C Bond Formation
下载免费PDF全文
![点击此处可从《Angewandte Chemie (International ed. in English)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Dr. Taiga Yurino Yohei Ueda Dr. Yoshiki Shimizu Dr. Shinji Tanaka Haruka Nishiyama Prof. Dr. Hayato Tsurugi Prof. Dr. Kazuhiko Sato Prof. Dr. Kazushi Mashima 《Angewandte Chemie (International ed. in English)》2015,54(48):14437-14441
A salt‐free procedure for the generation of a wide variety of metal(0) particles, including Fe, Co, Ni, and Cu, was achieved using 2,3,5,6‐tetramethyl‐1,4‐bis(trimethylsilyl)‐1,4‐diaza‐2,5‐cyclohexadiene ( 1 ), which reduced the corresponding metal precursors under mild conditions. Notably, Ni particles formed in situ from the treatment of Ni(acac)2 (acac=acetylacetonate) with 1 in toluene exhibited significant catalytic activity for reductive C? C bond‐forming reactions of aryl halides in the presence of excess amounts of 1 . By examination of high‐magnification transmission electron microscopy images and electron diffraction patterns, we concluded that amorphous Ni nanoparticles (Ni aNPs) were essential for the high catalytic activity. 相似文献