全文获取类型
收费全文 | 665篇 |
免费 | 27篇 |
国内免费 | 2篇 |
专业分类
化学 | 434篇 |
晶体学 | 3篇 |
力学 | 29篇 |
数学 | 68篇 |
物理学 | 160篇 |
出版年
2022年 | 4篇 |
2021年 | 15篇 |
2020年 | 9篇 |
2019年 | 8篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 19篇 |
2015年 | 17篇 |
2014年 | 20篇 |
2013年 | 39篇 |
2012年 | 53篇 |
2011年 | 59篇 |
2010年 | 25篇 |
2009年 | 22篇 |
2008年 | 37篇 |
2007年 | 42篇 |
2006年 | 34篇 |
2005年 | 40篇 |
2004年 | 21篇 |
2003年 | 21篇 |
2002年 | 22篇 |
2001年 | 6篇 |
2000年 | 15篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 7篇 |
1992年 | 9篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 9篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1978年 | 10篇 |
1977年 | 2篇 |
1976年 | 9篇 |
1975年 | 8篇 |
1974年 | 5篇 |
1973年 | 6篇 |
1972年 | 7篇 |
1926年 | 2篇 |
排序方式: 共有694条查询结果,搜索用时 250 毫秒
91.
We consider the variation of the coherent elastic scattering structure factor S(q) with momentum transfer q for a solution of block copolymers at finite concentration. We introduce the effect of concentration using a generalization of Zimm's model to copolymers which enables us to express intermolecular scattering functions in terms of intramolecular form factors only. We show that the shape of the scattering curve is very sensitive to the polymer concentration as well as to the contrast factors, the relative composition of co units, and the second virial coefficients characterizing constituents of the copolymer. In particular, we show that the scattering curve develops a maximum at low q for certain values of these parameters. We also discuss the variation of the apparent radius of gyration with polymer concentration. 相似文献
92.
Y. Lassailly C. Vettier F. Holtzberg A. Benoit J. Flouquet 《Solid State Communications》1984,52(8):717-719
Neutron diffraction experiments were performed on the divalent thulium compound TmTe. Magnetic structure determination leads to a type II antiferromagnet below the Néel temperature TN = .43 K. No crystal field excitations were observed. 相似文献
93.
We show that two dimensional electrons-holes droplets can exist in superlattice having a structural defect such as a layer with an additional atomic plane. This is a new and cleaner way to produce and study a plasma in two dimensions. 相似文献
94.
A. Dondos und H. Benoit 《Colloid and polymer science》1978,256(2):188
Ohne Zusammenfassung 相似文献
95.
Nuclear orientation experiments on 137mCe impurities in Al2La show directly at almost 0 K that these alloys correspond to the magnetic conditions assumed by Müller-Hartmann and Zittartz. 相似文献
96.
F. Benoit 《Journal of mass spectrometry : JMS》1973,7(12):1407-1413
The heat of formation of the benzoyl cation generated from [C6H5COX]+˙ is found to depend on X, while the heat of formation of the phenyl ion produced therefrom is, with one exception, independent of X. The excess energy of the benzoyl cation can be accounted for by an electronic excited state of the ion in the mass spectra of benzoic acid, benzaldehyde, benzamide, methyl benzoate and possibly benzophenone; the benzoyl cation is not excited in the mass spectra of acetophenone and benzoyl chloride. 相似文献
97.
Trifluoromethylated nitrogen-containing molecules have been shown to have important biological effects and their synthesis is in the focus of the pharmaceutical industry. In the last few years, simple nitrogen derivatives of fluoral, i.e. imines, acetals and oxazolidines, have emerged as powerful building blocks to synthesize these target molecules and relevant precursors. This review summarizes the chemistry of these "N-derivatives of fluoral", with special highlight on the syntheses of peptidomimetic units (amino alcohols, amino acids...) and heterocycles (piperidines, beta-lactams...). 相似文献
98.
Crecelius AC Cornett DS Caprioli RM Williams B Dawant BM Bodenheimer B 《Journal of the American Society for Mass Spectrometry》2005,16(7):1093-1099
We have developed a method to visualize matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI IMS) data aligned with optically determinable tissue structures in three dimensions. Details of the methodology are exemplified using the 3-D reconstruction of myelin basic protein (MBP) in the corpus callosum of a mouse brain. In this procedure, optical images obtained from serial coronal sections are first aligned to each other to reconstruct a surface of the corpus callosum from segmented contours of the aligned images. The MALDI IMS data are then coregistered to the optical images and superimposed into the surface to create the final 3-D visualization. Correlating proteomic data with anatomical structures provides a more comprehensive understanding of healthy and pathological brain functions, and holds promise to be utilized in more complex anatomical arrangements. 相似文献
99.
A. Dondos und H. Benoit 《Colloid and polymer science》1978,256(7):725
Ohne Zusammenfassung 相似文献
100.
Below T2 = 202 K, in the incommensurate phase, a Debye relaxation appears for c33; it can be attributed to a linear coupling between an acoustical mode and a phason. The relaxation time is τ = τ0/(T0?T) with τ0 = 6.2 x 10?12 sec deg and T0 = 200.9 K. The same phenomenon appears more weakly for c11. The c66 elastic constant has a double discontinuity around T1 = 169 K; this shows that in the vicinity of T1 there are two transitions, separated by a temperature interval of 3°. 相似文献