全文获取类型
收费全文 | 1826篇 |
免费 | 25篇 |
国内免费 | 44篇 |
专业分类
化学 | 826篇 |
晶体学 | 5篇 |
力学 | 55篇 |
综合类 | 14篇 |
数学 | 450篇 |
物理学 | 545篇 |
出版年
2024年 | 3篇 |
2023年 | 48篇 |
2022年 | 20篇 |
2021年 | 18篇 |
2020年 | 24篇 |
2019年 | 19篇 |
2018年 | 22篇 |
2017年 | 17篇 |
2016年 | 34篇 |
2015年 | 19篇 |
2014年 | 46篇 |
2013年 | 204篇 |
2012年 | 206篇 |
2011年 | 93篇 |
2010年 | 57篇 |
2009年 | 97篇 |
2008年 | 52篇 |
2007年 | 84篇 |
2006年 | 90篇 |
2005年 | 87篇 |
2004年 | 71篇 |
2003年 | 46篇 |
2002年 | 45篇 |
2001年 | 35篇 |
2000年 | 44篇 |
1999年 | 40篇 |
1998年 | 39篇 |
1997年 | 43篇 |
1996年 | 46篇 |
1995年 | 46篇 |
1994年 | 23篇 |
1993年 | 28篇 |
1992年 | 20篇 |
1991年 | 23篇 |
1990年 | 11篇 |
1989年 | 14篇 |
1988年 | 10篇 |
1987年 | 14篇 |
1986年 | 5篇 |
1985年 | 8篇 |
1984年 | 5篇 |
1983年 | 5篇 |
1982年 | 11篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 1篇 |
1974年 | 1篇 |
排序方式: 共有1895条查询结果,搜索用时 15 毫秒
101.
102.
Yu?A.?KarpovEmail author T.?A.?Makarova D.?F.?Makarov A.?P.?Kuznetsov 《Accreditation and quality assurance》2004,9(7):404-410
Problems verifying the accuracy of analyses of non-standardized materials for precious metal (PM) content have arisen at the Norilsky Nickel plant, which is a major producer of nickel, copper, and PMs in Russia. Because of the unavailability of certified reference samples for direct accuracy verification, a program of interlaboratory comparisons (ILC) was developed. This program was based on testing three semi-products of the PM production process for PM content. On program completion, a total of 826 results in 98 runs had been obtained. For each run, the calculated mean value of PM concentration was taken to be the reference value. The results obtained by Norilsky Nickel were in agreement with the reference values within the standard deviations calculated for the values. The quality of results yielded with the ILC program, as assessed via the Z-criterion, is regarded as satisfactory.Presented at the Second International Conference on Metrology – Trends and Applications in Calibration and Testing Laboratories, November 4–6, 2003, Eilat, Israel. 相似文献
103.
104.
105.
F. Michelot M. Rey 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,44(3):467-495
Effective vibronic Hamiltonian models are built for E ⊗e Jahn-Teller systems and analytical solutions are
obtained through Lie algebraic methods. Although approximate, we show that these models allow in particular to recover the
possible ground state crossover when quadratic couplings are present. The equivalence of E ⊗e and G' ⊗e
vibronic systems in cubic symmetry is precisely established through a particular realization of the electronic operators for
an
orbital quadruplet. We show how this equivalence is broken by a rovibronic interaction which, for a G' ⊗e system, still
gives an exactly solvable model. 相似文献
106.
107.
Hiroshi Yamatani 《Surface science》2007,601(22):5284-5288
We have developed an ultrahigh-vacuum (UHV) complex sample preparation and analysis system, which realizes a reliable surface science analyzing various characters on an identical surface. The system contains three sample-preparation-and-characterization chambers and five analysis chambers. They are (1) an electronic-properties-characterization chamber, (2) a magnetic-properties-characterization chamber, (3) an organic-molecule chamber, (4) UHV SEM, (5) a high-energy-resolution angle-resolved photoelectron spectrometer, (6) a high-energy-resolution display-type spherical mirror analyzer, (7) a room-temperature (RT) STM, and (8) an optical-properties characterization chamber. A special sample holder is used with six electrodes on it, which enables accurate temperature measurement of a sample by connecting a thermocouple directly to the sample even if it is transferred. Four other electrodes can be used for construction of various circuits including evaporators. Some examples are shown. 相似文献
108.
利用自组的光纤探头式光谱仪对载体肉类表面进行光谱测量,采用反向传播人工神经网络(BP-ANN)对肉类可见光谱进行识别,分析了隐层神经元、期望误差、判别输出范围等网络参数的调整对识别功能的影响.基于大量实测数据样本,优化网络结构参数选择,建立了良好的人工神经网络,对肉类光谱识别率达到97.5%. 相似文献
109.
复模糊数是模糊复分析中的基本概念,在模糊复分析中,它的运算是基于扩张原理的形式给出的,是对元素遍历某个条件所对应的结果进行运算,这种遍历过程给实际操作带来了很多的不便,因此,在一定程度上也阻碍了模糊复分析理论的应用.对此,本文基于模糊结构元的理论基础,探讨了复模糊数运算的另一种新的途径,这种方法简化了复模糊数的运算,也... 相似文献
110.
P. Chen Z. Policova C. R. Pace-Asciak A. W. Neumann 《Colloids and surfaces. B, Biointerfaces》1999,15(3-4):313-324
Molecular interactions between small molecules and proteins, such as binding of lipids to proteins, are of fundamental importance in various biological processes. A recently-developed method based on dynamic surface tension measurement is efficient and versatile in detecting such molecular interactions: Axisymmetric Drop Shape Analysis (ADSA) provides a tool for measuring the surface tension (γ) response to surface area changes. Through the analysis of the γ response pattern, surface competitive adsorption between small organic molecules and protein molecules can be detected. Surface squeeze-out of small molecules by proteins can also be observed. Molecular binding of lipids to proteins manifests itself in a modification of the γ response which is not compatible with a simple superposition of the two individual patterns. The specific binding can be studied in terms of dose effects and specificity. 相似文献