全文获取类型
收费全文 | 1146篇 |
免费 | 70篇 |
国内免费 | 1篇 |
专业分类
化学 | 886篇 |
晶体学 | 8篇 |
力学 | 13篇 |
数学 | 138篇 |
物理学 | 116篇 |
无线电 | 56篇 |
出版年
2023年 | 15篇 |
2022年 | 29篇 |
2021年 | 31篇 |
2020年 | 42篇 |
2019年 | 40篇 |
2018年 | 30篇 |
2017年 | 23篇 |
2016年 | 64篇 |
2015年 | 35篇 |
2014年 | 38篇 |
2013年 | 57篇 |
2012年 | 118篇 |
2011年 | 98篇 |
2010年 | 50篇 |
2009年 | 48篇 |
2008年 | 71篇 |
2007年 | 71篇 |
2006年 | 75篇 |
2005年 | 59篇 |
2004年 | 42篇 |
2003年 | 33篇 |
2002年 | 26篇 |
2001年 | 7篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1998年 | 3篇 |
1997年 | 8篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1989年 | 5篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 4篇 |
1981年 | 4篇 |
1980年 | 4篇 |
1979年 | 4篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1975年 | 4篇 |
1974年 | 5篇 |
1973年 | 2篇 |
1972年 | 4篇 |
1969年 | 2篇 |
1962年 | 2篇 |
1942年 | 2篇 |
排序方式: 共有1217条查询结果,搜索用时 15 毫秒
61.
62.
63.
64.
Theodore?J?Price Michael?D?Louria Damaries?Candelario-Soto Gregory?O?Dussor Nathanial?A?Jeske Amol?M?Patwardhan Anibal?Diogenes Amanda?A?Trott Kenneth?M?Hargreaves Christopher?M?FloresEmail author 《BMC neuroscience》2005,6(1):4
Background
Nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF) all play important roles in the development of the peripheral sensory nervous system. Additionally, these growth factors are proposed to modulate the properties of the sensory system in the adult under pathological conditions brought about by nerve injury or inflammation. We have examined the effects of NGF, GDNF and BDNF on adult rat trigeminal ganglion (TG) neurons in culture to gain a better understanding of how these growth factors alter the cytochemical and functional phenotype of these neurons, with special attention to properties associated with nociception. 相似文献65.
Jordan P Leach J Padgett M Blackburn P Isaacs N Goksör M Hanstorp D Wright A Girkin J Cooper J 《Lab on a chip》2005,5(11):1224-1228
We report the creation of permanent 3D configurations of cells, at predefined positions, within a gelatin matrix. The technique used holographic optical tweezers to manipulate individual E. coli within a solution comprising monomer precursors. The matrix was then set and after the laser beam was removed, we were able to demonstrate that the structures remained intact for many days. We were also able to demonstrate that, in the presence of appropriate nutrients, the E. coli survived within the gelatin matrix for several days. The technique could have a number of potential future applications, including the arrangement of a variety of different cell types in complex architectures, as motifs for promoting tissue differentiation and growth within the field of cell engineering. 相似文献
66.
This study examined the effect of presumed mismatches between speech input and the phonological representations of English words by native speakers of English (NE) and Spanish (NS). The English test words, which were produced by a NE speaker and a NS speaker, varied orthogonally in lexical frequency and neighborhood density and were presented to NE listeners and to NS listeners who differed in English pronunciation proficiency. It was hypothesized that mismatches between phonological representations and speech input would impair word recognition, especially for items from dense lexical neighborhoods which are phonologically similar to many other words and require finer sound discrimination. Further, it was assumed that L2 phonological representations would change with L2 proficiency. The results showed the expected mismatch effect only for words from dense neighborhoods. For Spanish-accented stimuli, the NS groups recognized more words from dense neighborhoods than the NE group did. For native-produced stimuli, the low-proficiency NS group recognized fewer words than the other two groups. The-high proficiency NS participants' performance was as good as the NE group's for words from sparse neighborhoods, but not for words from dense neighborhoods. These results are discussed in relation to the development of phonological representations of L2 words. (200 words). 相似文献
67.
68.
Using scanning tunneling microscopy, we show the phase transition between new structures of NO on Rh(111) in equilibrium with the gas phase near 300 K, in the Torr pressure range. Two phases with (2 x 2) and (3 x 3) periodicity transform into each other as the pressure and temperature change around the equilibrium P-T line. By measuring P and T at coexistence, we determined the heat of adsorption in the (3 x 3) structure. From the phase boundary dynamics, the activation energy barrier between phases were estimated. The results demonstrate that unique information can be obtained from high-pressure and high-temperature studies. 相似文献
69.