全文获取类型
收费全文 | 717篇 |
免费 | 25篇 |
国内免费 | 2篇 |
专业分类
化学 | 476篇 |
晶体学 | 4篇 |
力学 | 17篇 |
数学 | 92篇 |
物理学 | 155篇 |
出版年
2023年 | 8篇 |
2022年 | 9篇 |
2021年 | 13篇 |
2020年 | 19篇 |
2019年 | 13篇 |
2018年 | 14篇 |
2017年 | 16篇 |
2016年 | 25篇 |
2015年 | 25篇 |
2014年 | 25篇 |
2013年 | 45篇 |
2012年 | 47篇 |
2011年 | 61篇 |
2010年 | 29篇 |
2009年 | 32篇 |
2008年 | 35篇 |
2007年 | 27篇 |
2006年 | 37篇 |
2005年 | 49篇 |
2004年 | 31篇 |
2003年 | 20篇 |
2002年 | 25篇 |
2001年 | 15篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 11篇 |
1997年 | 6篇 |
1996年 | 8篇 |
1995年 | 5篇 |
1993年 | 4篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 6篇 |
1988年 | 8篇 |
1987年 | 4篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1982年 | 5篇 |
1981年 | 2篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1977年 | 3篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1974年 | 2篇 |
1966年 | 3篇 |
1963年 | 2篇 |
1958年 | 2篇 |
排序方式: 共有744条查询结果,搜索用时 29 毫秒
51.
Mariël G. Pikkemaat 《Analytical and bioanalytical chemistry》2009,395(4):893-905
Monitoring of food products from animal origin for the presence of antimicrobial residues is preferably done using microbial
screening methods because of their high cost-effectiveness. Traditionally applied methods fail to detect the maximum residue
limits which were established when EU Council Regulation 2377/90 came into effect. Consequently, during the last decade this
has led to the development of improved microbial screening methods. This review provides an overview of the efforts expended
to bring antibiotic screening methods into compliance with EU legislation. It can be concluded that the current situation
is still far from satisfactory. 相似文献
52.
Mariá Ernestina Chávez Rodríguez Angel López Gómez 《International Journal of Theoretical Physics》2001,40(1):95-104
The only pair of binary classical essential connectives for which the Artin braid relation holds is a distributive lattice, i.e. the Boolean disjunction and conjunction of 相似文献
53.
The response characteristics of the solid state cyanide ion selective electrode towards some benzylnitriles are investigated. In 10M KOH solution, the electrode exhibits nearly Nernstian response over the concentration range of 10–2 to 10–4
M of various substituted benzylnitriles with an anionic slope of 53–59 mV/concentration decade. The response time varies from 10 to 20 min depending on both the nature of the substituent group and the concentration of the nitrile compound. Direct potentiometric measurement of some nitrile compounds at the concentration level of 0.01 to 1 mg/ml shows an average recovery of 98.2% and a mean standard deviation of 2.3%. Many nitrogen functional groups do not interfere. 相似文献
54.
55.
Rapid solidification processing (cooling rate from the interval 105–106 K s−1) was used to prepare deeply undercooled cryolite-alumina melts. Such prepared samples were analyzed by the XRD method. Besides
cryolite, XRD patterns belonging to ι-Al2O3 were recorded. The influence of annealing on the XRD patterns of deeply undercooled melts was also investigated. 相似文献
56.
Liquid metal embrittlement (LME) of copper by liquid bismuth is investigated at 300°C. It is shown that a very rapid damage is due to the synergy between the external stress and the phenomenon of intergranular penetration (IGP). Tests of IGP, i.e. without external stress, were done at 300°C and at 600°C and have resulted in strong intergranular embrittlement due to the formation of nanometer-thick intergranular films, as measured and quantified by Auger electron spectroscopy (AES). The formation of these films is discussed with respect to apparently non-zero dihedral angles at 600°C. A general procedure based on mechanical testing and AES measurements, to check whether IGP has occurred or not, is outlined. This procedure can be seen as an alternative way to determine the wetting transition temperature. The presence of nanometer-thick films due to IGP is discussed with respect to the LME mechanisms. 相似文献
57.
Michal Korenko Marián Kucharík Jozef Vincenc Oboňa Dušan Janičkovič Rosa Córdoba José María De Teresa Blanka Kubíková 《Helvetica chimica acta》2008,91(7):1389-1399
The rapid‐solidification processing (by a cooling rate of 105–106 K/s) was used for the preparation of deeply undercooled cryolite/alumina (Na3AlF6/Al2O3) melts. We found a mass of nanotubes on the surface of these undercooled melts. The nanotubes were preferentially located on the defect places of the surface with the following approximate dimensions: base≈100×100 nm, length≈1000 nm. The solidified samples with the nanotubes on the surface were analyzed by scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), X‐ray diffraction (XRD), and infrared spectroscopy (IR). 相似文献
58.
In this paper, a constant heat transfer coefficient present in a nonlinear Robin‐type boundary condition associated with an elliptic equation is reconstructed uniquely from a single boundary energy measurement. Two types of such boundary energy measurement are considered, and solvability theorems for the solution of the resulting nonlinear inverse problems are provided. Further, one‐dimensional numerical results are presented and discussed. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
59.
Reyes Malavé Osuna Rocio Ponce Ortiz Mari Carmen Ruiz Delgado Valentin G Nenajdenko Viktor V Sumerin Elizabeth S Balenkova Víctor Hernández Juan Teodomiro López Navarrete 《Chemphyschem》2007,8(5):745-750
Herein, we study the conjugation properties of three different thienoacenes, each of which has three or four fused thiophene rings, by means of Fourier transform Raman spectroscopy. The B3LYP/6-31G** vibrational analysis of all of the collected spectroscopic data evidences that the selective enhancement of a limited number of Raman scatterings is related to the occurrence in the three thienoacenes of a vibronic coupling between the lowest unoccupied frontier molecular orbital (LUMO) and some Raman-active skeletal nu(C==C) stretching modes of 1600-1300 cm(-1). 相似文献
60.
Tomá? Gucky Eva ?ezní?ková Petr D?ubák Marián Hajdúch Vladimír Kry?tof 《Monatshefte für Chemie / Chemical Monthly》2010,55(7):709-714