全文获取类型
收费全文 | 422篇 |
免费 | 38篇 |
国内免费 | 1篇 |
专业分类
林业 | 40篇 |
农学 | 9篇 |
基础科学 | 4篇 |
89篇 | |
综合类 | 32篇 |
农作物 | 17篇 |
水产渔业 | 25篇 |
畜牧兽医 | 193篇 |
园艺 | 10篇 |
植物保护 | 42篇 |
出版年
2023年 | 6篇 |
2022年 | 10篇 |
2021年 | 19篇 |
2020年 | 22篇 |
2019年 | 17篇 |
2018年 | 22篇 |
2017年 | 20篇 |
2016年 | 17篇 |
2015年 | 19篇 |
2014年 | 29篇 |
2013年 | 25篇 |
2012年 | 34篇 |
2011年 | 49篇 |
2010年 | 26篇 |
2009年 | 17篇 |
2008年 | 26篇 |
2007年 | 22篇 |
2006年 | 12篇 |
2005年 | 20篇 |
2004年 | 15篇 |
2003年 | 9篇 |
2002年 | 10篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1984年 | 1篇 |
1972年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有461条查询结果,搜索用时 31 毫秒
101.
Marco Zampiga Luca Laghi Massimiliano Petracci Chenglin Zhu Adele Meluzzi Sami Dridi Federico Sirri 《畜牧与生物技术杂志(英文版)》2019,(1)
Background: Due to the important functions of arginine in poultry,it should be questioned whether the currently adopted dietary Arg:Lys ratios are sufficient to meet the modern broiler requirement in arginine.The present study aimed,therefore,to evaluate the effects of the dietary supplementation of L-arginine in a commercial broiler diet on productive performance,breast meat quality attributes,incidence and severity of breast muscle myopathies and foot pad dermatitis(FPD),and plasma and muscle metabolomics profile in fast-growing broilers.Results: A total of 1,170 1-day-old Ross 308 male chicks was divided into two experimental groups of 9 replicates each fed either a commercial basal diet(CON,digestible Arg:Lys ratio of 1.05,1.05,1.06 and 1.07 in each feeding phase,respectively) or the same basal diet supplemented on-top with crystalline L-arginine(ARG,digestible Arg:Lys ratio of 1.15,1.15,1.16 and 1.17,respectively).Productive parameters were determined at the end of each feeding phase(12,22,33,43 d).At slaughter(43 d),incidence and severity of FPD and breast myopathies were assessed,while plasma and breast muscle samples were collected and analyzed by proton nuclear magnetic resonancespectroscopy.The dietary supplementation of arginine significantly reduced cumulative feed conversion ratio compared to the control diet at 12 d(1.352 vs.1.401,P 0.05),22 d(1.398 vs.1.420; P 0.01) and 33 d(1.494 vs.1.524; P 0.05),and also tended to improve it in the overall period of trial(1.646 vs.1.675; P = 0.09).Body weight was significantly increased in ARG compared to CON group at 33 d(1,884 vs.1,829 g; P 0.05).No significant effect was observed on meat quality attributes,breast myopathies and FPD occurrence.ARG birds showed significantly higher plasma concentration of arginine and leucine,and lower of acetoacetate,glutamate,adenosine and proline.Arginine and acetate concentrations were higher,whereas acetone and inosine levels were lower in the breast of ARG birds(P 0.05).Conclusions: Taken together,these data showed that increased digestible Arg:Lys ratio had positive effects on feed efficiency in broiler chickens probably via modulation of metabolites that play key roles in energy and protein metabolism. 相似文献
102.
Tritrichomonas foetus and Mycoplasma felis coinfection in the upper respiratory tract of a cat with chronic purulent nasal discharge 下载免费PDF全文
Luca Pazzini Linda Mugnaini Francesca Mancianti Lorenzo Ressel 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2018,47(2):294-296
A 5‐year‐old indoor male neutered Siamese cat was presented with clinical signs of sneezing and chronic bilateral purulent nasal discharge. Multiple nasal cavity swabs were submitted for bacterial cultures, Mycoplasma felis‐DNA qPCR, and cytology. M felisqPCR was positive and cytomorphologic diagnosis was severe, acute, purulent, rhinitis with intralesional protozoal microorganisms consistent with a Trichomonas spp. Nested PCR (nPCR) confirmed the diagnosis of Tritrichomonas foetus. Systemic therapy with doxycycline for M felis and metronidazole for T foetus was started with remission of clinical signs within 2 weeks; however, symptoms relapsed shortly after therapy was discontinued. This study represents the first documented case of T foetus associated with chronic nasal discharge in a cat, which supports the hypothesis that T foetus can live in the nasal cavity. It is also the first reported case of M felis and T foetus coinfection, which indicates that with mycoplasmal feline upper respiratory tract infections, T foetus should be considered as a coinfecting agent. 相似文献
103.
High dose hypofractionated frameless volumetric modulated arc radiotherapy is a feasible method for treating canine trigeminal nerve sheath tumors 下载免费PDF全文
104.
105.
Seventeen Sustainable Development Goals (SDGs) were adopted by 193 Governments at the General Assembly of the United Nations in 2015 for achievement by 2030. These SDGs present a roadmap to a sustainable future and a challenge to the science community. To guide activities and check progress, targets and indicators have been and are still being defined. The soil science community has published documents that describe the primary importance of soil for SDGs addressing hunger, water quality, climate mitigation and biodiversity preservation, and secondary relevance of soil for addressing several other SDGs. Soil scientists only marginally participated in the SDG discussions and are currently only peripherally engaged in discussions on targets or indicators. Agreement on several soil‐related indicators has still not been achieved. Involvement of soil scientists in SDG‐based studies is desirable for both developing solutions and increasing the visibility of the soil profession. Inputs into policy decisions should be improved as SDG committee members are appointed by Governments. Possible contributions of soil science in defining indicators for the SDGs are explored in this paper. We advocate the pragmatic use of soil–water–atmosphere–plant simulation models and available soil surveys and soil databases where “representative” soil profiles for mapping units (genetically defined genoforms) are functionally expressed in terms of several phenoforms reflecting effects of different types of soil use and management that strongly affect functionality. 相似文献
106.
Claudia Becagli Umberto Di Salvatore Gianfranco Fabbio Ferretti Fabrizio Luca Salvati 《Journal of Sustainable Forestry》2013,32(3):234-250
ABSTRACTThe more and more diffused multifunctional role addressed nowadays to public forests, calls for targeted analysis aimed at highlighting the overall outcome of different practices implemented on the same forest compartment, according to the locally prevailing function. This study was carried out in four Italian beech forests across a latitudinal gradient representative of multiple management history, stand structure, and dominant stand age. We analyze forest structure at the compartment scale before and after silvicultural practices. We aim to explore relationships and similarities between 10 stand attributes (mensurational and structural variables) to identify relevant indicators for the monitoring and management of forest ecosystems. Results indicate changing patterns of correlation and similarity among mensurational variables following practice implementation. A sensitivity gradient to silvicultural practice was finally identified within the four sites investigated as a result of the diverging stand structure. Our approach suggests a way and provides an insight for the design of adaptive forestry management practices required to meet environmental targets, in addition to the already acknowledged supply of primary goods and services. 相似文献
107.
Jonathan N. King Mike Martin Valrie Chetboul Luca Ferasin Anne T. French Günther Strehlau Wolfgang Seewald Sarah G. W. Smith Simon T. Swift Susan L. Roberts Andrea M. Harvey Christopher J. L. Little Sarah M. A. Caney Kerry E. Simpson Andrew H. Sparkes Eleanor J. Mardell Eric Bomassi Claude Muller John P. Sauvage Armelle Diqulou Matthias A. Schneider Laurence J. Brown David D. Clarke Jean‐Francois Rousselot 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2019,33(6):2559-2571
108.
Matteo Alessandro Saladini Laura Asteggiano Marco Giuseppe Pansa Luca Giordani Luca Serre Graziano Vittone 《国际虫害防治杂志》2016,62(3):214-221
The European earwig, Forficula auricularia L. (Dermaptera: Forficulidae), is a well-known species that is cosmopolitan and present throughout Europe. Due to its omnivorous feeding behaviour, this species can act as a generalist predator, preying on several top fruit pests, but also as a pest causing shallow gouges or holes in stone and soft fruits such as apricots, strawberries, raspberries or blackberries. In Piedmont (NW Italy), significant fruit damage has been observed lately in apricot orchards where earwigs fed on ripening fruits and made a considerable part of the produce unmarketable. In this study, we sampled earwig populations in three apricot orchards in Piedmont and tested the effectiveness of glue barriers applied to the tree trunks in reducing both earwig density in the canopy and fruit damage. The arboreal glues Rampastop® and Vebicolla® were tested both in the field and laboratory trials. Glue barriers demonstrated to be effective control measures, significantly reducing earwig abundance in the canopy and fruit damage. Rampastop® gave better results on old trees with a very rough and cracked bark, since in that case Vebicolla® could not perfectly bond with the trunk. 相似文献
109.
Micrografts of internodes excised from in vitro grown pear plants (Pyrus communis L. cv. 'Bosc' (B) and cv. 'Butirra Hardy' (BH)) and quince (Cydonia oblonga Mill. East Malling clone C (EMC)), were cultured aseptically to test the effectiveness of their functional vascular reconnection in relation to incompatibility-compatibility relationships that these genotypes exhibit in the field. The incompatible heterograft (B/EMC) showed a marked delay in internode cohesion compared with the autografts (both B/B and BH/BH) and the compatible heterograft (BH/EMC). Even when fused, the translocation of [14C]-sorbitol from upper to lower internode was lower in B/EMC micrografts than in the other combinations. Epifluorescence studies performed with carboxyfluorescin, a specific phloem probe, indicated that the limited translocation was caused by a delay in the establishment of functional phloem continuity between the two internodes. In the B/EMC combination, new differentiated tracheary elements (TE) in the parenchyma tissue at the graft interface between the two internodes were not detected until 30 days after grafting, whereas in the BH/EMC heterograft and both autografts, new xylem connections appeared to cross the interface 20 days after grafting. Immunohistochemical detection (terminal nick-end labeling assay) of the number of cells undergoing nuclear DNA fragmentation at the graft interface confirmed that the limited and delayed TE differentiation in B/EMC heterografts was associated with a decrease in the activity of programmed cell death processes involved in the differentiation of TE. 相似文献
110.
Luca Pipino Marie-Christine Van Labeke Andrea Mansuino Valentina Scariot Annalisa Giovannini Leen Leus 《Euphytica》2011,178(2):203-214
Fertility of hybrid tea roses is often reduced due to their interspecific origin but also to intensive inbreeding. New genotypes
used as pollen donors represent an economic risk for a breeding programme, as their influence on seed production is unknown.
In this study 11 cut rose genotypes were selected from a company database as high fertile or low fertile male parents, according
to the number of seeds per hybridisation. Pollen morphology and in vitro germination of the selected genotypes were characterised.
Pollen was either small (mean diameter <30 μm), shrunken, and irregular (abnormal), or large (mean diameter >30 μm), elliptical
and crossed by furrows (normal). High correlations were found between the number of seeds produced per hybridisation and the
pollen diameter (r = 0.94) or the percentage of normal pollen (r = 0.96). In order to evaluate the predictive power of the models, we conducted regression analyses and performed a validation
experiment on genotypes not present in the database and without background information on fertility. Pollen diameter and percentage
of normal pollen were characterised and fitted in the regression models for seed set predictions. Validation with an independent
dataset gave a good prediction for 83.3% of the data. This indicates that using either the mean pollen diameter or the percentage
of normal pollen resulted in effective fertility prediction. This tool could enhance the genetic variability in crossings
between hybrid tea roses, thus creating possibilities for less economically risky exploitation of new tetraploid genotypes
as male parents. 相似文献