全文获取类型
收费全文 | 151896篇 |
免费 | 1569篇 |
国内免费 | 379篇 |
专业分类
化学 | 81623篇 |
晶体学 | 1827篇 |
力学 | 6655篇 |
综合类 | 7篇 |
数学 | 15284篇 |
物理学 | 48448篇 |
出版年
2020年 | 1116篇 |
2019年 | 1174篇 |
2018年 | 1476篇 |
2017年 | 1455篇 |
2016年 | 2469篇 |
2015年 | 1548篇 |
2014年 | 2425篇 |
2013年 | 6315篇 |
2012年 | 4929篇 |
2011年 | 6256篇 |
2010年 | 4281篇 |
2009年 | 4290篇 |
2008年 | 5693篇 |
2007年 | 5764篇 |
2006年 | 5404篇 |
2005年 | 4994篇 |
2004年 | 4410篇 |
2003年 | 3855篇 |
2002年 | 3884篇 |
2001年 | 4335篇 |
2000年 | 3316篇 |
1999年 | 2572篇 |
1998年 | 2241篇 |
1997年 | 2184篇 |
1996年 | 1981篇 |
1995年 | 1897篇 |
1994年 | 1886篇 |
1993年 | 1727篇 |
1992年 | 1991篇 |
1991年 | 2119篇 |
1990年 | 1917篇 |
1989年 | 1916篇 |
1988年 | 1856篇 |
1987年 | 1755篇 |
1986年 | 1658篇 |
1985年 | 2156篇 |
1984年 | 2299篇 |
1983年 | 1866篇 |
1982年 | 2051篇 |
1981年 | 1937篇 |
1980年 | 1857篇 |
1979年 | 2009篇 |
1978年 | 2177篇 |
1977年 | 2050篇 |
1976年 | 2090篇 |
1975年 | 2004篇 |
1974年 | 2059篇 |
1973年 | 2044篇 |
1972年 | 1341篇 |
1971年 | 1197篇 |
排序方式: 共有10000条查询结果,搜索用时 213 毫秒
141.
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
142.
A.F. Mesquita A.O. Porto G.M. de Lima J.M. Delgado F.S. Lameiras 《Solid State Communications》2005,136(3):133-137
Hexagonal and cubic cadmium selenide were prepared from a chemical route by using cadmium chloride and potassium selenium hydride obtained from reaction of selenium powder and potassium boron hydride. The product obtained was thermally treated under argon flux at 300, 500 and 600 °C for 2 h and characterized by X-ray photoelectron spectroscopy and X-ray diffraction. The X-ray diffraction data were refined by Rietveld method and the structural parameters were determined for the phases of each annealed samples. At 300 °C five phases were identified: Cubic and hexagonal cadmium selenides and the contaminants: Potassium chloride, boron oxide and cadmium boron oxide. At 500 and 600 °C only the hexagonal cadmium selenide phase was identified besides the other above mentioned contaminant. 相似文献
143.
F. Gallego y Gómez 《Fresenius' Journal of Analytical Chemistry》1938,112(3-4):135-160
Ohne Zusammenfassung 相似文献
144.
F. Hartogs 《Mathematische Zeitschrift》1937,42(1):144-150
Ohne Zusammenfassung 相似文献
145.
I. M. Kolthoff S. R. Cooper V. J. Tulane F. Reimers H. A. J. Pieters K. Höppner V. H. Matula C. B. Macek W. N. Skworzow J. S. Schepelewa F. Čuta K. Kámen S. Cohen R. E. Oesper D. S. Narayanamurthi T. R. Seshadri H. M. State A. W. Kirssanow W. M. Tscherkassow D. M. Mukherjee T. Akiyama Y. Mine S. Yabe Y. Volmar M. Déribéré 《Analytical and bioanalytical chemistry》1937,111(5-6):192-197
146.
F. Richter 《Analytical and bioanalytical chemistry》1940,119(3-4):109-118
147.
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
148.
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
149.
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
150.
J E Paanakker J M Thio H M Van den Wildenberg F M Kaspersen 《Journal of chromatography. A》1987,421(2):327-335
An assay has been developed and validated for the routine monitoring of vecuronium in plasma. It consists of solid-phase extraction using C18 disposables as sample pre-treatment, high-performance liquid chromatography and post-column ion-pair extraction with fluorimetric detection. The fluorescent anion 9,10-dimethoxyanthracene-2-sulphonate (DAS) is used as the counter ion. The detection limit is ca. 5 ng/ml in plasma with a signal-to-noise ratio of 10. The assay is also applicable for monitoring vecuronium and its potential metabolites in other biological media, e.g., urine, bile and tissue (liver, kidney) homogenates. 相似文献