全文获取类型
收费全文 | 252189篇 |
免费 | 1583篇 |
国内免费 | 405篇 |
专业分类
化学 | 115608篇 |
晶体学 | 3469篇 |
力学 | 13584篇 |
综合类 | 7篇 |
数学 | 39728篇 |
物理学 | 81781篇 |
出版年
2019年 | 1173篇 |
2018年 | 10432篇 |
2017年 | 11288篇 |
2016年 | 6592篇 |
2015年 | 2422篇 |
2014年 | 2540篇 |
2013年 | 6440篇 |
2012年 | 9320篇 |
2011年 | 18804篇 |
2010年 | 11516篇 |
2009年 | 11638篇 |
2008年 | 16453篇 |
2007年 | 20082篇 |
2006年 | 5605篇 |
2005年 | 11981篇 |
2004年 | 7911篇 |
2003年 | 7317篇 |
2002年 | 5323篇 |
2001年 | 4489篇 |
2000年 | 3630篇 |
1999年 | 2615篇 |
1998年 | 2287篇 |
1997年 | 2205篇 |
1996年 | 2157篇 |
1995年 | 2002篇 |
1994年 | 1976篇 |
1993年 | 1805篇 |
1992年 | 2070篇 |
1991年 | 2198篇 |
1990年 | 1996篇 |
1989年 | 2003篇 |
1988年 | 1950篇 |
1987年 | 1851篇 |
1986年 | 1778篇 |
1985年 | 2285篇 |
1984年 | 2434篇 |
1983年 | 1993篇 |
1982年 | 2167篇 |
1981年 | 2056篇 |
1980年 | 1979篇 |
1979年 | 2138篇 |
1978年 | 2314篇 |
1977年 | 2098篇 |
1976年 | 2182篇 |
1975年 | 2072篇 |
1974年 | 2120篇 |
1973年 | 2155篇 |
1972年 | 1392篇 |
1971年 | 1235篇 |
1968年 | 1177篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
F. Pijlman 《Few-Body Systems》2005,36(1-4):209-213
Within the theoretical framework which we apply, a suggested origin for single-spin asymmetries is the presence of gauge links in transverse momentum-dependent distribution functions. Recently we found new gauge-link structures in a number of hard processes. These structures need to be considered in the evolution of parton distribution functions and for establishing factorization. 相似文献
152.
J.-C. Thomas L. Achouri J. Äystö R. Béraud B. Blank G. Canchel S. Czajkowski P. Dendooven A. Ensallem J. Giovinazzo N. Guillet J. Honkanen A. Jokinen A. Laird M. Lewitowicz C. Longour F. de Oliveira Santos K. Peräjärvi M. Stanoiu 《The European Physical Journal A - Hadrons and Nuclei》2004,21(3):419-435
153.
Dimitar I. Pushkarov 《Central European Journal of Physics》2004,2(3):420-455
Basic ideas and results which characterize quantum diffusion of defects in quantum crystals like solid helium as a new phenomenon
are presented. Quantum effects in such media lead to a delocalization of point defects (vacancies, impurities etc.) and they
turn into quasiparticles of a new type—defectons, which are characterized not by their position in the crystal lattice but
by their quasimomentum and dispersion law. Defecton-defecton and defecton-phonon scattering are considered and an interpolation
formula for the diffusion coefficient valid in all interesting temperature and concentration regions is presented. A comparison
with the experimental data is made. Some alternative points of view are discussed in detail and the inconsistency of the Kisvarsanyi-Sullivan
theory is shown. 相似文献
154.
J. Krause und F. Umland 《Fresenius' Journal of Analytical Chemistry》1989,335(7):791-795
Summary This paper presents some applications of cyclic voltammetry at the interface of two immiscible electrolyte solutions by means of an experimental set-up described in a former publication. When using special sample preparation good results are obtained for the determination of iodide and quinine in pharmaceutical products as well as for the determination of quinine in tonic water and dodecylsulfate in a tooth-salt.
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
Herrn Prof. Dr. Günther Tölg zum 60. Geburtstag gewidmet 相似文献
155.
Summary The available laboratory data of turbulent boundary layer flow over two-dimensional obstacles have been examined in order
to identify the parameters (such as the aspect ratio or the surface roughness) driving the onset of separation. A comparison
with some linearized models suitable for atmospheric applications is also made. It results that i) the model response can
be highly sensitive to the detailed shape of the obstacle; ii) the ratio between obstacle length and boundary layer thickness
is relevant in determining the pressure perturbation near the surface; iii) the surface shear stress is poorly described in
most cases and in particular in the obstacle wake.
Riassunto I dati di laboratorio disponibili, relativi a strati limite turbolenti su ostacoli bidimensionali, sono stati esaminati al fine di identificare i parametri guida della separazione (quali la pendenza o la rugosità della superficie). Inoltre è stato fatto un confronto con i risultati di alcuni modelli linearizzati adatti per applicazioni atmosferiche. Ne risulta che i) la risposta del modello è molto sensibile alla forma dettagliata dell’ostacolo; ii) il rapporto fra la lunghezza dell’ostacolo e lo spessore dello strato limite turbolento incidente è importante nel determinare la perturbazione della pressione vicino alla superficie; iii) lo ?shear stress? superficiale non è riprodotto con accuratezza nella maggioranza dei casi, in particolare nella scia dell’ostacolo.
Резюме Анализируются имеющиеся лабораторные данные по турбулентному течению в пограничном слое над двумерными препятствиями, чтобы идентифицировать параметры (такие как аспектное отношение или шероховатость поверхности), определяющие возникновение отрыва. Проводится сравнение с некоторыми линеаризованными моделями, удобными для атмосферных приложений. Получены следующие результаты: 1) модельный отклик может быть очень чувствительным к детальной форме препятствия; 2) отношение между длиной препятствия и толщиной поверхностного слоя является существенным при определении возмущения давления вблизи поверхности; 3) напряжение поверхностного сдвига плохо описывается в большинстве случаев и, в частности, в спутной струе.相似文献
156.
Blood serum samples were irradiated by monochromatic synchrotron radiation (15 keV) and by 2.4-MeV protons to compare their performance for the detection of trace elements by x-ray fluorescence (XRF) spectrometry. Absolute concentration assignment was based on the addition of an internal standard and on a method which uses the incoherent and coherent radiation as a flux monitor of the incoming beam. Preliminary experiments with a synchrotron XRF microprobe are reported. 相似文献
157.
158.
T.S. Khlebnicova V.G. Isakova A.V. Baranovsky E.V. Borisov F.A. Lakhvich 《Journal of fluorine chemistry》2006,127(12):1564-1569
A one-pot synthesis of 2-perfluoroalkanoylcyclohexane-1,3-diones via C-acylation of cyclohexane-1,3-diones with N-perfluoroacylimidazole as an acylating agent is reported. A reaction was examined with isolated N-trifluoroacetylimidazole and with N-perfluoroacylimidazoles generated in situ from perfluorocarboxylic acid anhydrides or perfluorocarboxylic acids. 相似文献
159.
P.A. Grillet 《Acta Mathematica Hungarica》2005,106(4):301-315
Summary Three weak variants of compactness which lie strictly between compactness and quasicompactness, are introduced. Their basic properties are studied. The interplay with mapping and their direct and inverse preservation under mappings are investigated. In the process three decompositions of compactness are observed. 相似文献
160.