全文获取类型
收费全文 | 9563篇 |
免费 | 373篇 |
国内免费 | 52篇 |
专业分类
化学 | 5365篇 |
晶体学 | 220篇 |
力学 | 216篇 |
综合类 | 41篇 |
数学 | 1463篇 |
物理学 | 2683篇 |
出版年
2023年 | 53篇 |
2022年 | 100篇 |
2021年 | 152篇 |
2020年 | 111篇 |
2019年 | 167篇 |
2018年 | 211篇 |
2017年 | 176篇 |
2016年 | 305篇 |
2015年 | 246篇 |
2014年 | 319篇 |
2013年 | 740篇 |
2012年 | 443篇 |
2011年 | 524篇 |
2010年 | 405篇 |
2009年 | 390篇 |
2008年 | 426篇 |
2007年 | 410篇 |
2006年 | 344篇 |
2005年 | 312篇 |
2004年 | 303篇 |
2003年 | 422篇 |
2002年 | 328篇 |
2001年 | 310篇 |
2000年 | 220篇 |
1999年 | 157篇 |
1998年 | 136篇 |
1997年 | 106篇 |
1996年 | 94篇 |
1995年 | 134篇 |
1994年 | 74篇 |
1993年 | 72篇 |
1992年 | 91篇 |
1991年 | 61篇 |
1990年 | 86篇 |
1989年 | 78篇 |
1988年 | 77篇 |
1987年 | 76篇 |
1986年 | 78篇 |
1985年 | 113篇 |
1984年 | 127篇 |
1983年 | 76篇 |
1982年 | 84篇 |
1981年 | 88篇 |
1980年 | 101篇 |
1979年 | 68篇 |
1978年 | 73篇 |
1977年 | 78篇 |
1976年 | 68篇 |
1975年 | 64篇 |
1974年 | 51篇 |
排序方式: 共有9988条查询结果,搜索用时 218 毫秒
81.
J. Gronkowski M. Lefeld-Sosnowska I. Zakościelna-Minor 《Zeitschrift für Physik B Condensed Matter》1988,72(3):399-402
Fringes in the dislocation image in X-ray section topography are shown to fade away partially when unpolarized radiation is used. The fading effect is explained in terms of an analogy with the polarization beat in a wedge crystal. The polarization nature of the phenomenon is confirmed through numerical simulations of the contrast.Dedicated to Professor Dr. Ulrich Bonse on the occasion of his 60th birthday 相似文献
82.
Creep resistance investigations of the Al-40 wt % Zn alloy at room temperature have been performed and revealed some creep compliance. Additions of Cu and Si decrease considerably the preliminary creep compliance in the alloy which then turn to be dimensionally stable and resistant to creep. Tensile test investigations performed at different deformation rates have not revealed the existance of the superplastic deformation mechanism.Presented at the 4th International Symposium on Plasticity of Metals and Alloys, September 711, 1987, Srni, Czechoslovakia. 相似文献
83.
Robert J. Budzyński Sławomir Klimek Paweł Sadowski 《Communications in Mathematical Physics》1989,120(3):481-499
Motivated by the operator formulation of conformal field theory on Riemann surfaces, we study the properties of the infinite dimensional group of local biholomorphic transformations (conformal reparametrizations) of 1 and develop elements of its representation theory. 相似文献
84.
85.
Ion-selective electrode with cellulose triacetate membrane containing nonactin is employed for the potentiometric detection of ammonia produced in biocatalytic reaction in flow-injection system with enzyme reactor. The elimination of interferences occurring in the presence of alkali metal ions was achieved by covering a nonactin membrane with outer hydrophobic gas permeable membrane. The obtained flow-injection response to ammonia indicates a possibility of ammonia determination down to 10 microM ammonia. In the flow-injection system for urea determination 200 microl of 10-fold diluted blood serum sample was injected into carrier stream of distilled water merged with TRIS buffer, passed through the urease flow-through reactor and then after merging with NaOH stream delivered to the detector. It was found in several series of natural blood serum samples, that the correction for endogenous ammonia in such a determination is not indispensable. 相似文献
86.
电化学超级电容器电极材料的研究进展 总被引:9,自引:0,他引:9
回顾了电化学超级电容器电极材料的研究进展,并对不同电极材料的储能原理和性能特点进行了简要的阐述。参考文献29篇。 相似文献
87.
滂胺天蓝-氨基糖苷类抗生素的显色反应及其分析应用 总被引:6,自引:1,他引:6
在 pH2.0~7.0的条件下 ,滂胺天蓝(PSB)与硫酸卡那霉素(KANA)、硫酸庆大霉素(GEN)和硫酸新霉素(NEO)等氨基糖苷类抗生素反应生成蓝色离子缔合物 ,最大显色波长位于686~690nm ,线性范围分别为0~14.0、0~12.5、0~14.0mg/L ,摩尔吸光系数(ε)分别为1.53×104、1.12×104、1.47×104L/(mol·cm) ;最大褪色波长位于620~622nm ,线性范围分别为0~14.0、0~12.0、0~14.0mg/L ,摩尔吸光系数(ε)分别为1.41×104、1.43×104、2.42×104L/(mol·cm) ;当用双波长叠加法测定时 ,ε值分别为2.94×104、2.55×104、3.89×104L/(mol·cm) ;探讨了适宜的反应条件 ;该法用于市售药物中氨基糖苷类抗生素含量的测定 ,结果令人满意 相似文献
88.
A method ("electrosorption") has been developed for separation of silver from copper by its deposition through internal electrolysis with hydrogen adsorbed on a platinum surface. The silver can then be stripped and determined by atomic-absorption spectrometry or the dithizone method. The activation of the platinum surface with adsorbed hydrogen can be achieved either electrolytically or by passing hydrogen gas through the solution in which the platinum is immersed. The method of electrosorption has been successfully applied to determination of trace levels of silver in copper metal. 相似文献
89.
90.
Suńol J. J. Saurina J. Carrillo F. Colom X. 《Journal of Thermal Analysis and Calorimetry》2003,72(2):753-758
Comparison of Lyocell, modal and viscose fibers was performed by means of differential scanning calorimetry, thermogravimetry
and scanning electron microscopy. Thermal analysis was performed in air atmosphere. Samples were mercerized (21.3 g 100 mL-1)
or submitted to solar radiation (seven months). Solar degraded samples presents a higher thermal stability and are initially
less degraded. Furthermore, Lyocell fiber is the most stable under thermal degradation conditions. Heating produces a reduction
of the fiber diameter (about 50%).
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献