全文获取类型
收费全文 | 322篇 |
免费 | 25篇 |
专业分类
林业 | 41篇 |
农学 | 13篇 |
61篇 | |
综合类 | 11篇 |
农作物 | 14篇 |
水产渔业 | 19篇 |
畜牧兽医 | 138篇 |
园艺 | 16篇 |
植物保护 | 34篇 |
出版年
2023年 | 7篇 |
2022年 | 3篇 |
2021年 | 8篇 |
2020年 | 7篇 |
2019年 | 10篇 |
2018年 | 10篇 |
2017年 | 14篇 |
2016年 | 13篇 |
2015年 | 9篇 |
2014年 | 9篇 |
2013年 | 24篇 |
2012年 | 23篇 |
2011年 | 29篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 27篇 |
2007年 | 15篇 |
2006年 | 22篇 |
2005年 | 15篇 |
2004年 | 11篇 |
2003年 | 19篇 |
2002年 | 13篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 4篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1976年 | 1篇 |
1970年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有347条查询结果,搜索用时 15 毫秒
81.
Brandt's cormorant diet (1994–2012) indicates the importance of fall ocean conditions for northern anchovy in central California 下载免费PDF全文
Meredith L. Elliott Annie E. Schmidt Sara Acosta Russell Bradley Pete Warzybok Keith M. Sakuma John C. Field Jaime Jahncke 《Fisheries Oceanography》2016,25(5):515-528
Effective ecosystem‐based management requires a comprehensive understanding of the functional links in the system. In many marine systems, forage species constitute a critical link between primary production and upper trophic level marine predators. As top predators, seabirds can be indicators of the forage species they consume and the ocean processes that influence these populations. We analyzed the diet and breeding success for the years 1994, 2003, 2005, and 2007–2012 of the Brandt's cormorant (Phalacrocorax penicillatus), a piscivorous diving seabird, breeding in central California, to evaluate the extent to which cormorant diet composition relates to prey availability, and how diet composition relates to breeding success and ocean conditions. Cormorant diet was primarily composed of young‐of‐the‐year (YOY) northern anchovy (Engraulis mordax), YOY rockfish (Sebastes spp.), and several species of small flatfish (order Pleuronectiformes). YOY rockfish consumption was positively related to their abundance as measured in a late spring pelagic midwater trawl survey. Northern anchovy appeared to be the most important prey as its consumption was positively related to cormorant breeding success. More northern anchovy were consumed in years where warm‐water conditions prevailed in the fall season before cormorant breeding. Thus, warm ocean conditions in the fall appear to be an important contributing factor in producing a strong year‐class of northern anchovy in central California and consequently a strong‐year class of Brandt's cormorant on the Farallon Islands. 相似文献
82.
Shanise Lisie Mello El Halal Elessandra da Rosa Zavareze Annie Campello Telles Ricardo Marques e Silva Márcia de Mello Luvielmo 《Journal Of Aquatic Food Product Technology》2013,22(4):507-517
ABSTRACTProteins have been used extensively because of their relative abundance, nutritional qualities, and film-forming ability with a good structural integrity and mechanical properties. This study investigated the effects of protein isolate and glycerol concentration and pH on the properties of protein films obtained from Whitemouth croaker (Micropogonias furnieri) residues. The films were evaluated for mechanical properties, thickness, water solubility, water vapor permeability (WVP), and morphological properties. The lowest water solubility of the films occurred at low pHs and low glycerol concentrations. The films had high elongation and higher tensile strength when prepared with higher concentrations of protein isolate, lower concentrations of glycerol, and at lower pHs. The WVP and thickness of the films had a low correlation coefficient. The films were rough and had irregular surfaces. These results indicated that protein isolates from fish of low commercial value can be used as a component of new polymeric films for packaging. However, more studies are needed to assess their barrier action against oxygen, thermal behaviors, and their performance in different types of packaging. 相似文献
83.
Steven W Purcell Annie Mercier Chantal Conand Jean‐François Hamel M Verónica Toral‐Granda Alessandro Lovatelli Sven Uthicke 《Fish and Fisheries》2013,14(1):34-59
Worldwide, most sea cucumber fisheries are ineffectively managed, leading to declining stocks and potentially eroding the resilience of fisheries. We analyse trends in catches, fishery status, fishing participation and regulatory measures among 77 sea cucumber fisheries through data from recent fishery reports and fishery managers. Critical gaps in fisheries biology knowledge of even commonly targeted species undermine the expected success of management strategies. Most tropical fisheries are small‐scale, older and typified by numerous (>8) species, whereas temperate fisheries are often emerging, mono‐specific and industrialized. Fisher participation data indicated about 3 million sea cucumber fishers worldwide. Fisher participation rates were significantly related to the average annual yield. permanova analysis showed that over‐exploited and depleted fisheries employed different sets of measures than fisheries with healthier stocks, and a non‐metric multidimensional scaling ordination illustrated that a broad set of regulatory measures typified sustainable fisheries. SIMPER and regression tree analyses identified that the dissimilarity was most related to enforcement capacity, number of species harvested, fleet (vessel) controls, limited entry controls and rotational closures. The national Human Development Index was significantly lower in countries with over‐exploited and depleted fisheries. Where possible, managers should limit the number of fishers and vessel size and establish short lists of permissible commercial species in multispecies fisheries. Our findings emphasize an imperative to support the enforcement capacity in low‐income countries, in which risk of biodiversity loss is exceptionally high. Solutions for greater resilience of sea cucumber stocks must be embedded within those for poverty reduction and alternative livelihood options. 相似文献
84.
Logan SM Chen W Aubry A Gidney MA Lacelle S St Michael F Kuolee R Higgins M Neufeld S Cox AD 《Veterinary microbiology》2006,116(1-3):175-186
Previous structural studies of the lipopolysaccharides from the veterinary pathogens Mannheimia haemolytica (Mh), Actinobacillus pleuropneumoniae (Ap) and Pasteurella multocida (Pm) had identified a conserved inner core oligosaccharide structure that was present in all strains investigated. In order to examine the potential of this inner core structure as a vaccine, a mutagenesis strategy was adopted to interrupt a D-glycero-D-manno-heptosyltransferase gene (losB) of Mh. This gene encodes the enzyme responsible for the addition of a D-glycero-D-manno-heptose residue, the first residue beyond the conserved inner core, and its inactivation exposed the conserved inner core structure as a terminal unit on the mutant LPS molecule. Subsequent analyses confirmed the targeted structure of the mutant LPS had been obtained, and complementation with losB in trans confirmed that the losB gene encodes an alpha-1,6-D-glycero-D-manno-heptosyltransferase. Monoclonal antibodies raised in mice to this LPS structure were found to recognise LPS and whole-cells of the truncated mutant and wild-type Mh. The antibodies were bactericidal against a wild-type Mh strain and were able to passively protect mice in a model of Mh disease. This illustrates that it is possible to raise functional antibodies against the conserved inner core LPS structure. 相似文献
85.
86.
Annie Bézier Bernard Lambert Fabienne Baillieul 《European journal of plant pathology / European Foundation for Plant Pathology》2002,108(2):111-120
Defense responses of grapevine towards Botrytis cinerea were investigated. The expression of genes coding for proteins involved in defense were studied: (a) phenylalanine ammonia-lyase (PAL) and stilbene synthase (StSy), (b) an acidic chitinase (VCH3) and a basic chitinase (VCHIT1b), and (c) a polygalacturonase inhibitor protein (PGIP). Since no PGIP was known in grapevine, a complete cDNA sequence was first characterized by PCR and RACE-PCR amplifications. RNAs isolated from infected leaves and infected berries were analysed by semi-quantitative and real-time RT-PCRs. In infected leaves, the expression of PAL, StSy, PGIP and VCH3 genes occurred 6hours post inoculation (hpi). Increase of VCHIT1b gene expression was delayed (24hpi). Maximum levels of induction of these genes were observed at 48hpi, except for the VCH3 gene (24hpi). Activation of these defense responses was not sufficient to stop B. cinerea spread. In berries, no VCH3 gene expression was detected. Maximum levels of induction were observed in stage 3 (loss of berry colour and abundant production of conidia) for the PAL and PGIP genes, and in stage 4 (shrivelled berry) for the StSy and VCHIT1b genes. 相似文献
87.
Anne‐Sophie Walker Annie Micoud Florent Rémuson Jacques Grosman Michel Gredt Pierre Leroux 《Pest management science》2013,69(6):667-678
Resistance to fungicides is an evolutionary process resulting from the selection of advantageous genotypes in naturally diverse populations. Seven fungicide modes of action are authorised to control grey mould caused by Botrytis cinerea on grapevine in France, and five of them have encountered specific resistance, with variable frequencies in populations and possible consequences for field fungicide efficacy. Moreover, multidrug resistance is caused by fungicide efflux and allows a weak resistance towards six unrelated modes of action. Here, a review is given of the fungicide resistance status of B. cinerea in France, particularly in the vineyards of Champagne, which are the most affected. Recently developed resistance and recent findings concerning the associated resistance mechanisms are focused upon in particular. Finally, antiresistance strategies are presented, and examples of managed resistance are discussed in a more general manner with the aim of extending this knowledge to other crops and countries undergoing similar resistance problems. © 2013 Society of Chemical Industry 相似文献
88.
Yigalelad Y. Ben-Yephet Michal Reuven L Mor Shulamit Manulis C. Shoham G. Forer M. J. Berlinger Lea Bar Nir D. Wool S. Cohen D. Veierov N. Aharonson Annie Fenigstein A. R. Horowitz N. C. Toscano D. Gerung Pnina Rapid D. Gerling Shalom W. Applebaum M. Klein B. Raccah R. G. Kenneth 《Phytoparasitica》1989,17(3):223-236
89.
90.
Brice Marolleau Aurélien Petiteau Marie-Noëlle Bellanger Mélanie Sannier Nadège Le Pocreau Laetitia Porcher Sophie Paillard Fabrice Foucher Tatiana Thouroude Laurana Serres-Giardi Gabriela Aguileta Annie Chastellier Caroline Bonneau Bruno Le Cam Vanessa Soufflet-Freslon Laurence Hibrand-Saint Oyant 《Plant pathology》2020,69(6):1093-1107
The haploid ascomycete Diplocarpon rosae is the causal agent of black spot disease on roses, a widespread and devastating disease in the outdoor landscape. In this study, we established a Eurasian collection of 77 monoconidial strains of D. rosae: 50 strains collected on cultivated roses in Europe and Asia, and 27 strains on wild roses in Kazakhstan. To provide tools to describe its biology and to study its genetic diversity, we sequenced two strains of D. rosae using Illumina paired-end technology. The genome sizes of these two strains were estimated at 31.1 and 35.2 Mb, which are two times smaller than the genome size of the unique strain previously published. A BUSCO analysis confirmed a genome duplication of the strain previously sequenced and partial gene duplication of strains analysed in this study. Using the two genome sequences, 27 polymorphic microsatellite markers were identified. Polymorphism analysis of the 77 strains revealed a strong genetic differentiation between strains from cultivated and wild roses, and a lower diversity within the fungal population from cultivated roses compared to the population from wild roses. Pathogenicity of 10 strains was evaluated on 9 rose cultivars inoculated in the greenhouse. Disease scoring allowed the classification of strains into three groups and the characterization of resistance of rose cultivars. Good correlation observed between resistance scoring in greenhouse conditions and in the field indicates that pathogenicity assays in controlled conditions could be very useful in the near future to rapidly characterize the resistance of new rose varieties to black spot disease. 相似文献