首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1155篇
  免费   23篇
  国内免费   6篇
化学   914篇
晶体学   11篇
力学   2篇
数学   42篇
物理学   215篇
  2023年   8篇
  2020年   14篇
  2019年   10篇
  2018年   13篇
  2017年   14篇
  2016年   15篇
  2015年   13篇
  2014年   21篇
  2013年   80篇
  2012年   56篇
  2011年   57篇
  2010年   44篇
  2009年   40篇
  2008年   73篇
  2007年   73篇
  2006年   66篇
  2005年   52篇
  2004年   60篇
  2003年   54篇
  2002年   43篇
  2001年   20篇
  2000年   11篇
  1999年   15篇
  1998年   10篇
  1997年   9篇
  1996年   7篇
  1995年   8篇
  1994年   9篇
  1993年   8篇
  1992年   8篇
  1991年   12篇
  1990年   8篇
  1989年   12篇
  1988年   6篇
  1986年   12篇
  1985年   15篇
  1984年   19篇
  1983年   6篇
  1982年   13篇
  1981年   11篇
  1980年   19篇
  1979年   17篇
  1978年   18篇
  1977年   12篇
  1976年   12篇
  1975年   14篇
  1974年   13篇
  1973年   18篇
  1971年   5篇
  1968年   6篇
排序方式: 共有1184条查询结果,搜索用时 546 毫秒
101.
A wide class of Higgs sectors is investigated in supersymmetric standard models. When the lightest Higgs boson (h  ) looks the standard model one, the mass (mhmh) and the triple Higgs boson coupling (the hhh   coupling) are evaluated at the one-loop level in each model. While mhmh is at most 120–130 GeV in the minimal supersymmetric standard model (MSSM), that in models with an additional neutral singlet or triplet fields can be much larger. The hhh coupling can also be sensitive to the models: while in the MSSM the deviation from the standard model prediction is not significant, that can be 30–60% in some models such as the MSSM with the additional singlet or with extra doublets and charged singlets. These models are motivated by specific physics problems like the μ-problem, the neutrino mass, the scalar dark matter and so on. Therefore, when h   is found at the CERN Large Hadron Collider, we can classify supersymmetric models by measuring mhmh and the hhh coupling accurately at future collider experiments.  相似文献   
102.
A series of diphenylamino-substituted phenylene-(poly)ethynylenes were successfully synthesized by a combination of Sonogashira coupling and double elimination protocol of β-substituted sulfones. When UV-light was irradiated, the amino-substituted phenylene-(poly)ethynylene emitted strong luminescence. The emission underwent a large bathochromic shift in polar solvent because of stabilization of their charge-separated excited states. Analyses of fluorescence life times of aminoacetylenes revealed that radiationless process was suppressed in the polar solvent CH2Cl2, resulting in high quantum yields.  相似文献   
103.
6,13-Diiododibenzo[a,h]anthracene and 5,8-diiodopicene were synthesized by AuCl-catalyzed double cyclization. The highly selective reaction yielded a new class of peri-halogenated fused aromatics.  相似文献   
104.
Abstract

Interactions of glucopyranose, fructopyranose and sucrose with a proteinaceous receptor model have been examined to validate the stereomolecular mechanisms of sweet taste proposed for sugars. The methylene groups at C-6 of glucose, at C-1 and C-6 of fructose and at C-6, C-1' and C-6' of sucrose appear to play an important role as dispersive interaction centres with the receptor.  相似文献   
105.
106.
Summary Boric and germanic acids were detected by a conductivity detector after ion-exclusion Chromatographic separation on a cation-exchange resin. Neither acid could be directly measured by a conductivity detector because they were very weak. However, use of eluents of polyol compounds permitted their determination by a conductivity detector. With 0.1 M of fructose as eluent, it was possible to detect 0.5 ppb of boric acid (as B) and 1.5 ppb of germanic acid (as Ge).
HPLC-Bestimmung von Borsäure und Germaniumsäure mit konduktometrischer Detection
Zusammenfassung Beide Säuren wurden mit Hilfe eines Leitfähigkeitsdetektors nach Trennung durch Ionenausschluß-Chromatographie an einem Kationenaustauscher analysiert. Eine direkte Messung war wegen der Schwäche der Säuren nicht möglich; daher wurde eine Elution mit Polyolen durchgeführt. Mit 0,1 M Fructoselösung als Eluens konnten noch 0,5 ppb Borsäure (als B) und 1,5 ppb Germaniumsäure (als Ge) nachgewiesen werden.
  相似文献   
107.
A positron pulsing system for an intense positron beam generated by an electron linac is reported. The pulsing system generates an intense pulsed positron beam of variable energy and variable pulse period. The pulsed positron beam is used as a non-destructive probe for various material research. In this paper, we also discuss applications of the pulsed positron beam: positron lifetime spectroscopy, age-momentum correlation spectroscopy, positronium time-of-flight measurement, and positron annihilation-induced Auger electron spectroscopy with a time-of-flight technique.  相似文献   
108.
109.
Hadronic modes in the quark-gluon plasma and their spectral properties are discussed on the basis of the lattice QCD data analyzed by the maximum entropy method.Arrival of the final proofs: 25 March 2005PACS: 12.38.Mh, 12.38.Gc  相似文献   
110.
Self‐organization plays an imperative role in recent materials science. Highly tunable, periodic structures based on dynamic self‐organization at micrometer scales have proven difficult to design, but are desired for the further development of micropatterning. In the present study, we report a microgroove array that spontaneously forms on a p‐type silicon surface during its electrodissolution. Our detailed experimental results suggest that the instability can be classified as Turing instability. The characteristic scale of the Turing‐type pattern is small compared to self‐organized patterns caused by the Turing instabilities reported so far. The mechanism for the miniaturization of self‐organized patterns is strongly related to the semiconducting property of silicon electrodes as well as the dynamics of their surface chemistry.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号