全文获取类型
收费全文 | 1494篇 |
免费 | 13篇 |
国内免费 | 11篇 |
专业分类
化学 | 689篇 |
晶体学 | 34篇 |
力学 | 18篇 |
数学 | 101篇 |
物理学 | 676篇 |
出版年
2021年 | 8篇 |
2020年 | 9篇 |
2019年 | 10篇 |
2017年 | 8篇 |
2016年 | 9篇 |
2015年 | 12篇 |
2014年 | 21篇 |
2013年 | 49篇 |
2012年 | 56篇 |
2011年 | 110篇 |
2010年 | 38篇 |
2009年 | 24篇 |
2008年 | 60篇 |
2007年 | 82篇 |
2006年 | 98篇 |
2005年 | 79篇 |
2004年 | 45篇 |
2003年 | 35篇 |
2002年 | 44篇 |
2001年 | 34篇 |
2000年 | 32篇 |
1999年 | 35篇 |
1998年 | 32篇 |
1997年 | 20篇 |
1996年 | 48篇 |
1995年 | 37篇 |
1994年 | 40篇 |
1993年 | 50篇 |
1992年 | 47篇 |
1991年 | 25篇 |
1990年 | 22篇 |
1989年 | 13篇 |
1988年 | 15篇 |
1987年 | 16篇 |
1986年 | 24篇 |
1985年 | 20篇 |
1984年 | 12篇 |
1983年 | 10篇 |
1982年 | 12篇 |
1981年 | 12篇 |
1980年 | 13篇 |
1979年 | 12篇 |
1978年 | 15篇 |
1977年 | 12篇 |
1975年 | 12篇 |
1973年 | 13篇 |
1970年 | 6篇 |
1969年 | 6篇 |
1967年 | 6篇 |
1962年 | 6篇 |
排序方式: 共有1518条查询结果,搜索用时 31 毫秒
21.
Dula Amarasiriwardena Steven F. Durrant Alexandra Lásztity Antoaneta Kvska Mark D. Argentine Ramon M. Barnes 《Microchemical Journal》1997,56(3):352-372
Semiquantitative analysis with accuracy of ±30 to 50% is a valuable tool for rapid screening of samples prior to quantitative determination of trace metals. In this study semiquantitative analysis software available with commercial inductively coupled plasma–mass spectrometry (ICP-MS) instrumentation is applied for rapid multielemental analysis, and the accuracy and precision of this semiquantitative analysis approach is evaluated with biological certified reference materials. Samples were prepared by high-pressure, high-temperature nitric acid vapor-phase digestion. For most elements the measured semiquantitative results are in the range of the certified values. With appropriate analyte solution dilution, the measured concentrations of the major elements (e.g., Ca) also agree with certified values. The accuracy is within ±10% for 28 element determinations that include 16 individual elements (Ag, As, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Rb, Sb, Sr, Tl, and Zn) and ±20% for 54 element determinations that include three more elements (Mg, V, and U) in eight certified reference materials including water. The method precision is 11 ± 11% (relative standard deviation,n= 65). 相似文献
22.
The photometric and fluorometric characteristics of the complex formed by 1,4-dihydroxyanthraquinone with Y(III) in 20–80% water-ethanol solution are described by the study of several variables. The stoichiometry and stability constant of the complex in the solution are 1:1 and log K = 4.57, respectively. The 1,4-dihydroxyanthraquinone-Y(III) solid complex has been prepared and studied by infrared spectroscopy and thermal analysis. The thermal behavior of this compound has been studied using thermogravimetry and differential scanning calorimetry techniques and the residue verified by X-ray diffraction. 相似文献
23.
J. M. Calvert D. G. Lees D. J. Derry D. Barnes 《Journal of Radioanalytical and Nuclear Chemistry》1972,12(2):271-275
The various nuclear techniques which have been used to study oxygen self-diffusion in oxides are discussed. Results are given
for measurements using resonance capture in the18O(p, α)15N and18O(p, γ)19F reactions and the different techniques are compared. 相似文献
24.
Recent advances in several experimental techniques have enabled detailed structural information to be obtained for floating (Langmuir) monolayers and Langmuir-Blodgett films. These techniques are described briefly and their application to the study of films of fatty acids and their salts is discussed. Floating monolayers on aqueous subphases have been shown to possess a complex polymorphism with phases whose structures may be compared to those of smectic mesophases. However, only those phases that exist at high surface pressures are normally used in Langmuir-Blodgett (LB) deposition. In single LB monolayers of fatty acids and fatty acid salts the acyl chains are in the all-trans conformation with their long axes normal to the substrate. The in-plane molecular packing is hexagonal with long-range bond orientational order and short-range positional order: known as the hexatic-B structure. This structure is found irrespective of the phase of the parent floating monolayer. The structures of multilayer LB films are similar to the structures of their bulk crystals, consisting of stacked bilayer lamellae. Each lamella is formed from two monolayers of fatty acid molecules or ions arranged head to head and held together by hydrogen bonding between pairs of acids or ionic bonding through the divalent cations. With acids the acyl chains are tilted with respect to the substrate normal and have a monoclinic structure, whereas the salts with divalent cations may have the chains normal to the substrate or tilted. The in-plane structures are usually centred rectangular with the chains in the trans conformation and packed in a herringbone pattern. Multilayer films of the acids show only a single-step order-disorder transition at the melting point. This temperature tends to rise as the number of layers increases. Complex changes occur when multilayer films of the salts are heated. Disorder of the chains begins at low temperatures but the arrangement of the head groups does not alter until the melting temperature is reached. Slow heating to a temperature just below the melting temperature gives, with some salts, a radical change in phase. The lamellar structure disappears and a new phase consisting of cylindrical rods lying parallel to the substrate surface and stacked in a hexagonal pattern is formed. In each rod the cations are aligned along the central axis surrounded by the disordered acyl chains. 相似文献
25.
Abe F Albrow M Amidei D Anway-Wiese C Apollinari G Atac M Auchincloss P Azzi P Bacchetta N Baden AR Badgett W Bailey MW Bamberger A de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Beretvas A Berge JP Bertolucci S Biery K Bhadra S Binkley M Bisello D Blair R Blocker C Bodek A Bolognesi V Booth AW Boswell C Brandenburg G Brown D Buckley-Geer E Budd HS Busetto G 《Physical review letters》1995,74(6):855-859
26.
Limits on WWZ and WW gamma couplings from WW and WZ production in pp-bar collisions at sqrt s=1.8TeV
Abe F Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Apollinari G Areti H Atac M Auchincloss P Azfar F Azzi P Bacchetta N Badgett W Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Bertolucci S Bhatti A Biery K Binkley M Bird F Bisello D Blair RE Blocker C Bodek A Bokhari W Bolognesi V Bortoletto D Boswell C Boulos T 《Physical review letters》1995,75(6):1017-1022
27.
Abe F Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Apollinari G Areti H Atac M Auchincloss P Azfar F Azzi P Bacchetta N Badgett W Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Bertolucci S Bhatti A Biery K Binkley M Bird F Bisello D Blair RE Blocker C Bodek A Bokhari W Bolognesi V Bortoletto D Boswell C Boulos T 《Physical review letters》1995,75(6):1012-1016
28.
Abe F Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Apollinari G Areti H Atac M Auchincloss P Azfar F Azzi P Bacchetta N Badgett W Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Bertolucci S Bhatti A Biery K Binkley M Bird F Bisello D Blair RE Blocker C Bodek A Bokhari W Bolognesi V Bortoletto D Boswell C Boulos T 《Physical review letters》1995,75(24):4358-4363
29.
Abe F Akimoto H Akopian A Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Aota S Apollinari G Asakawa T Ashmanskas W Atac M Auchincloss P Azfar F Azzi-Bacchetta P Bacchetta N Badgett W Bagdasarov S Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Bertolucci S Bhatti A Biery K Binkley M Bisello D Blair RE Blocker C 《Physical review letters》1995,75(22):3997-4002
30.
Abe F Albrow MG Amendolia SR Amidei D Antos J Anway-Wiese C Apollinari G Areti H Atac M Auchincloss P Azfar F Azzi P Bacchetta N Badgett W Bailey MW Bao J de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Bartalini P Bauer G Baumann T Bedeschi F Behrends S Belforte S Bellettini G Bellinger J Benjamin D Benlloch J Bensinger J Benton D Beretvas A Berge JP Bertolucci S Bhatti A Biery K Binkley M Bird F Bisello D Blair RE Blocker C Bodek A Bokhari W Bolognesi V Bortoletto D Boswell C Boulos T 《Physical review letters》1995,74(18):3538-3543