全文获取类型
收费全文 | 149篇 |
免费 | 11篇 |
专业分类
林业 | 7篇 |
农学 | 1篇 |
基础科学 | 2篇 |
30篇 | |
综合类 | 14篇 |
农作物 | 11篇 |
水产渔业 | 4篇 |
畜牧兽医 | 78篇 |
园艺 | 2篇 |
植物保护 | 11篇 |
出版年
2023年 | 6篇 |
2022年 | 1篇 |
2021年 | 10篇 |
2020年 | 4篇 |
2019年 | 7篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 4篇 |
2015年 | 8篇 |
2014年 | 6篇 |
2013年 | 13篇 |
2012年 | 11篇 |
2011年 | 12篇 |
2010年 | 6篇 |
2009年 | 2篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 1篇 |
2003年 | 2篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1982年 | 1篇 |
1966年 | 1篇 |
1947年 | 1篇 |
1934年 | 1篇 |
排序方式: 共有160条查询结果,搜索用时 46 毫秒
1.
2.
Anja Hartmann Kathrin Becker Ulf Karsten Daniel Remias Markus Ganzera 《Marine drugs》2015,13(10):6291-6305
Mycosporine-like amino acids (MAAs), a group of small secondary metabolites found in algae, cyanobacteria, lichens and fungi, have become ecologically and pharmacologically relevant because of their pronounced UV-absorbing and photo-protective potential. Their analytical characterization is generally achieved by reversed phase HPLC and the compounds are often quantified based on molar extinction coefficients. As an alternative approach, in our study a fully validated hydrophilic interaction liquid chromatography (HILIC) method is presented. It enables the precise quantification of several analytes with adequate retention times in a single run, and can be coupled directly to MS. Excellent linear correlation coefficients (R2 > 0.9991) were obtained, with limit of detection (LOD) values ranging from 0.16 to 0.43 µg/mL. Furthermore, the assay was found to be accurate (recovery rates from 89.8% to 104.1%) and precise (intra-day precision: 5.6%, inter-day precision ≤6.6%). Several algae were assayed for their content of known MAAs like porphyra-334, shinorine, and palythine. Liquid chromatography-mass spectrometry (LC-MS) data indicated a novel compound in some of them, which could be isolated from the marine species Catenella repens and structurally elucidated by nuclear magnetic resonance spectroscopy (NMR) as (E)-3-hydroxy-2-((5-hydroxy-5-(hydroxymethyl)-2-methoxy-3-((2-sulfoethyl)amino)cyclohex-2-en-1-ylidene)amino) propanoic acid, a novel MAA called catenelline. 相似文献
3.
Wittig W Hoffmann K Müller H Johne R 《Berliner und Münchener tier?rztliche Wochenschrift》2007,120(3-4):113-119
Between 2000 and 2004 a disease occurred in an aviary in Germany affecting various bird species belonging to the order Passeriformes including Collared Grosbeaks (Mycerobas affinis), Eurasian Bullfinches (Pyrrhula pyrrhula griseiventris), Brown Bullfinches (Pyrrhula nipalensis), Grey-headed bullfinches (Pyrrhula erythaca) and Yellow-bellied Tits (Periparus venustulus).The major clinical signs included increased mortality of fledglings and young birds, as well as feather disorders and feather loss in adult birds. In addition, adult Eurasian Bullfinches showed in one year a disease course, in which the major symptom was inflammation of the skin beginning on the basis of the beak and spreading over the head occurring a few days before death. Bacteriological and parasitological investigations did not reveal any consistent findings. Using a newly developed polymerase chain reaction protocol, DNA of the recently discovered finch polyomavirus (FPyV) was demonstrated in several affected birds. Because of the consistent detection of FPyV-DNA and the similarity of the symptoms with those observed during infection with the closely related avian polyomavirus in other bird species, an etiological role of FPyV in the observed disease is assumed. 相似文献
4.
5.
6.
7.
8.
Faham S Watanabe A Besserer GM Cascio D Specht A Hirayama BA Wright EM Abramson J 《Science (New York, N.Y.)》2008,321(5890):810-814
Membrane transporters that use energy stored in sodium gradients to drive nutrients into cells constitute a major class of proteins. We report the crystal structure of a member of the solute sodium symporters (SSS), the Vibrio parahaemolyticus sodium/galactose symporter (vSGLT). The approximately 3.0 angstrom structure contains 14 transmembrane (TM) helices in an inward-facing conformation with a core structure of inverted repeats of 5 TM helices (TM2 to TM6 and TM7 to TM11). Galactose is bound in the center of the core, occluded from the outside solutions by hydrophobic residues. Surprisingly, the architecture of the core is similar to that of the leucine transporter (LeuT) from a different gene family. Modeling the outward-facing conformation based on the LeuT structure, in conjunction with biophysical data, provides insight into structural rearrangements for active transport. 相似文献
9.
Role of histone H3 lysine 27 methylation in X inactivation 总被引:1,自引:0,他引:1
Plath K Fang J Mlynarczyk-Evans SK Cao R Worringer KA Wang H de la Cruz CC Otte AP Panning B Zhang Y 《Science (New York, N.Y.)》2003,300(5616):131-135
The Polycomb group (PcG) protein Eed is implicated in regulation of imprinted X-chromosome inactivation in extraembryonic cells but not of random X inactivation in embryonic cells. The Drosophila homolog of the Eed-Ezh2 PcG protein complex achieves gene silencing through methylation of histone H3 on lysine 27 (H3-K27), which suggests a role for H3-K27 methylation in imprinted X inactivation. Here we demonstrate that transient recruitment of the Eed-Ezh2 complex to the inactive X chromosome (Xi) occurs during initiation of X inactivation in both extraembryonic and embryonic cells and is accompanied by H3-K27 methylation. Recruitment of the complex and methylation on the Xi depend on Xist RNA but are independent of its silencing function. Together, our results suggest a role for Eed-Ezh2-mediated H3-K27 methylation during initiation of both imprinted and random X inactivation and demonstrate that H3-K27 methylation is not sufficient for silencing of the Xi. 相似文献
10.
Richter Jana Baltruschat Helmut Kabrodt Kathrin Schellenberg Ingo 《植物病害和植物保护杂志》2011,118(3-4):109-118
Journal of Plant Diseases and Protection - The importance of herbal plants is evident in the prevalent use as flavoring ingredients in food. However, meeting the growing demand for organic grown... 相似文献