全文获取类型
收费全文 | 94篇 |
免费 | 4篇 |
专业分类
林业 | 17篇 |
农学 | 2篇 |
31篇 | |
综合类 | 10篇 |
农作物 | 4篇 |
水产渔业 | 2篇 |
畜牧兽医 | 17篇 |
园艺 | 9篇 |
植物保护 | 6篇 |
出版年
2022年 | 1篇 |
2020年 | 2篇 |
2019年 | 1篇 |
2018年 | 2篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2014年 | 3篇 |
2013年 | 3篇 |
2012年 | 8篇 |
2011年 | 13篇 |
2010年 | 4篇 |
2009年 | 5篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 7篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 4篇 |
2001年 | 1篇 |
1999年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1987年 | 1篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有98条查询结果,搜索用时 171 毫秒
21.
Jaine H. H. L. de Oliveira Mirna H. R. Seleghim Christoph Timm Achim Grube Matthias K?ck Gislene G.F. Nascimento Ana Claudia T. Martins Elissa G. O. Silva Ana Olívia de Souza Paulo R. R. Minarini Fabio C. S. Galetti Célio L. Silva Eduardo Hajdu Roberto G. S. Berlinck 《Marine drugs》2006,4(1):1-8
Cyclostellettamines A – F (1 – 6) isolated from the sponge Pachychalina sp. and cyclostellettamines G - I, K and L (7 – 11) obtained by synthesis were evaluated in bioassays of antimicrobial activity against susceptible and antibiotic-resistant Staphylococcus aureus, Pseudomonas aeruginosa and antibiotic-susceptible Escherichia coli and Candida albicans, as well as in antimycobacterial activity against Mycobacterium tuberculosis H37Rv bioassays. The results obtained indicated that cyclostellettamines display different antimicrobial activity depending on the alkyl-chain size, suggesting that, if a mechanism-of action is implied, it is dependent on the distance between the two pyridinium moieties of cyclostellettamines. 相似文献
22.
Jürgen Scherkenbeck Hubert Dyker Daniel Gondol Achim Harder Andrew Plant Felix Reichel 《Pest management science》1999,55(4):457-461
A mono-proline analogue of the potent anthelmintic cyclooctadepsipeptide PF1022A has been synthesized. NMR studies in combination with molecular dynamics simulations demonstrate that the confirmation of this analogue is both rigidified and distorted compared with the asymmetric conformation of PF1022A. The backbone conformation is significant with respect to anthelmintic activity. © 1999 Society of Chemical Industry 相似文献
23.
Klaus G. Tietjen Joachim F. Kluth Roland Andree Michael Haug Markus Lindig Klaus H. Müller Heinz J. Wroblowsky Achim Trebst 《Pest management science》1991,31(1):65-72
The QB binding niche of photosystem II is also the binding site for many different herbicides. In order to understand the mode of binding of the herbicides, a 3-dimensional model of the binding niche was constructed. The model was based upon a comparison of the known structure of the QB binding niche in purple bacteria with sequence and mutant data of the D-1 protein of photosystem II. Plastoquinone builds up hydrogen bonds to phenylalanine 265 backbone amide nitrogen, to serine 264 hydroxyl, and to histidine 215 delta-1 nitrogen. In addition to these hydrogen bond donors and acceptors, herbicides can build up hydrogen bonds to backbone carbonyl of alamine 263 and to serine 268 hydroxyl. This is supported by binding data of inhibitors in Chlamydomonas reinhardtii chloroplasts of wild type and of five D-1 protein mutants (Ser264 Ala, Ala251 Val, Phe255Tyr, Val2191le, Leu275Phe). 相似文献
24.
Haemmerle G Lass A Zimmermann R Gorkiewicz G Meyer C Rozman J Heldmaier G Maier R Theussl C Eder S Kratky D Wagner EF Klingenspor M Hoefler G Zechner R 《Science (New York, N.Y.)》2006,312(5774):734-737
Fat tissue is the most important energy depot in vertebrates. The release of free fatty acids (FFAs) from stored fat requires the enzymatic activity of lipases. We showed that genetic inactivation of adipose triglyceride lipase (ATGL) in mice increases adipose mass and leads to triacylglycerol deposition in multiple tissues. ATGL-deficient mice accumulated large amounts of lipid in the heart, causing cardiac dysfunction and premature death. Defective cold adaptation indicated that the enzyme provides FFAs to fuel thermogenesis. The reduced availability of ATGL-derived FFAs leads to increased glucose use, increased glucose tolerance, and increased insulin sensitivity. These results indicate that ATGL is rate limiting in the catabolism of cellular fat depots and plays an important role in energy homeostasis. 相似文献
25.
Julie Barrette David Pothier David Auty Alexis Achim Isabelle Duchesne Nancy Gélinas 《Annals of Forest Science》2012,69(5):603-615
Context
To increase the wood supply to its industry, the government of Québec has allocated dead and sound wood (recently dead merchantable stems, DSW) to the wood supply chain in addition to the annual allowable cut of living trees. However, DSW is often criticized by sawmillers for its perceived poor quality and lower value.Aims
The objective of this study was to compare the lumber visual grade yield and value from live and recently dead merchantable trees in three different states of wood decomposition.Methods
In total, 162 black spruce trees [Picea mariana (Mill.) BSP] were felled from three different sites comprising three different states of wood decomposition and three diameter classes. The state of decomposition of each standing tree was categorized following Hunter??s classification (decay stages 1 & 2, 3 and 4) and the DSW classification developed by the Government of Québec.Results
Large trees (> 20?cm) of the Hunter 4 class have a lower value as a result of inferior quality.Conclusion
Considering the current economic difficulties facing the forest industry and the requirements of ecosystem-based management, we recommend leaving in the forest trees that have reached such a state of deterioration. 相似文献26.
David Auty Aaron R. Weiskittel Alexis Achim John R. Moore Barry A. Gardiner 《Annals of Forest Science》2012,69(1):93-104
• Context
The frequency, size, and insertion angle of primary branches are important determinants of wood quality and can be significantly influenced by silvicultural activities. 相似文献27.
Saint André Av Blackwell NM Hall LR Hoerauf A Brattig NW Volkmann L Taylor MJ Ford L Hise AG Lass JH Diaconu E Pearlman E 《Science (New York, N.Y.)》2002,295(5561):1892-1895
Parasitic filarial nematodes infect more than 200 million individuals worldwide, causing debilitating inflammatory diseases such as river blindness and lymphatic filariasis. Using a murine model for river blindness in which soluble extracts of filarial nematodes were injected into the corneal stroma, we demonstrated that the predominant inflammatory response in the cornea was due to species of endosymbiotic Wolbachia bacteria. In addition, the inflammatory response induced by these bacteria was dependent on expression of functional Toll-like receptor 4 (TLR4) on host cells. 相似文献
28.
Perisic N Afseth NK Ofstad R Kohler A 《Journal of agricultural and food chemistry》2011,59(18):10052-10061
The objective of this study was to investigate the influence of NaCl and two salt substitutes, MgSO4 and KCl, in different concentrations (1.5, 6.0, and 9.0%) on meat proteins by using Fourier transform infrared (FTIR) microspectroscopy. Hydration properties and secondary structural properties of proteins were investigated by studying the amide I, amide II, and water regions (3500-3000 cm(-1)) in FTIR spectra. By applying multivariate analysis (PCA and PLSR), differences between samples according to salt concentration and salt type were found and correlated to spectral bands. The most distinctive differences related to salt type were obtained by using the water region. It was found that samples salted with MgSO4 exhibited hydration and subsequent denaturation of proteins at lower concentrations than those salted with NaCl. Samples salted with KCl brines showed less denaturation even at the 9.0% concentration. The FTIR results were further supported by water-binding capacity (WBC) measurements. 相似文献
29.
Achim D Gruber Martin Peters Andreas Knieriem Peter Wohlsein 《Journal of zoo and wildlife medicine》2002,33(2):139-144
A 25-yr-old male captive walrus (Odobenus rosmarus divergens Illiger) died after suffering from periods of inactivity, anorexia, and weight loss for 8 wk. Necropsy revealed prominent, generalized atherosclerosis of cardiac arteries with widespread chronic myocardial infarction. Severe disseminated myocardial fibrosis most likely resulted in insidious cardiac failure that was ultimately the cause of death. Bouts of abdominal pain and disseminated cutaneous ulcers that had been observed 3 and 4 days before death, respectively, were attributed to circulatory failure and thrombosis. The cause of the vascular lesions remains unknown. When compared with humans, atherosclerosis is rare in animals and has not been described in a walrus. 相似文献
30.
Long-term downward distribution of global fallout 137Cs was studied in different soil types, in natural and semi-natural environments of four Chilean climatic zones. The 137Cs soil content showed an exponential decrease with depth; relaxation depth ranged from 0.9 cm in the polar climate environment up to 6.8 cm in the mesothermal warm summer one. In the Antarctic and Westpatagonic ecosystems the long freezing periods delayed the 137Cs leaching. In temperate and tropical climate zones, primarily the rates of annual rainfall and volume of coarse soil pores control the radionuclide's distribution in the soil profiles. 相似文献