全文获取类型
收费全文 | 169篇 |
免费 | 6篇 |
专业分类
林业 | 13篇 |
农学 | 5篇 |
基础科学 | 9篇 |
47篇 | |
综合类 | 9篇 |
农作物 | 3篇 |
水产渔业 | 11篇 |
畜牧兽医 | 77篇 |
园艺 | 1篇 |
出版年
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 7篇 |
2016年 | 3篇 |
2015年 | 3篇 |
2014年 | 2篇 |
2013年 | 4篇 |
2012年 | 6篇 |
2011年 | 20篇 |
2010年 | 7篇 |
2009年 | 8篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 9篇 |
2005年 | 10篇 |
2004年 | 15篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2001年 | 6篇 |
2000年 | 8篇 |
1999年 | 5篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1992年 | 7篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1986年 | 2篇 |
1984年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有175条查询结果,搜索用时 218 毫秒
101.
102.
The Effects of Soil Amendments on the Growth of Atriplex halimus and Bituminaria bituminosa in Heavy Metal-Contaminated Soils 总被引:1,自引:0,他引:1
In Southern Spain, as in other semi-arid zones, plants used for the phytoremediation of heavy metal-contaminated sites must
be able to withstand not only the challenging soil conditions but also seasonal drought and high temperatures. A pot assay
was carried out to determine the ability of soil amendments to promote the survival and growth of the seedlings of two native
species, Atriplex halimus L. (Amaranthaceae) and Bituminaria bituminosa (L.) C.H. Stirton (Fabaceae), in two heavy metal-contaminated soils, one of which also had a high level of arsenic (As).
Restriction of A. halimus shoot growth in the non-amended soils appeared to be due to deficiency of nitrogen, phosphorus (P) and potassium (K) and
in the more highly contaminated soil to lead (Pb) toxicity. Shoot biomass of A. halimus in the more highly contaminated soil was increased significantly by compost addition, due to increased uptake of K and P
and decreased tissue Pb. The lack of effect of compost on B. bituminosa growth in this soil, despite a large increase in tissue K, may have been due to elevated tissue levels of As and Pb and the
high soil salinity. The combination of A. halimus and compost addition seems appropriate for the phytostabilisation of contaminated semi-arid sites. 相似文献
103.
Ana Qui?ones Belén Martínez-Alcántara J. Miguel Martínez M. ángeles Forner-Giner Domingo J. Iglesias Eduardo Primo-Millo Francisco Legaz 《Water, air, and soil pollution》2012,223(5):2209-2222
The fate of 15N-labeled potassium nitrate (8.5% 15N excess) was determined in 3-year-old Valencia orange trees grown in 1-m3 containers filled with different textured soils (sandy and loamy). The trees were fertilized either in spring (24 March) or summer (24 July). Spring fertilized trees gave higher fruit yields in sandy than in loamy soils, which exceeded summer fertilized trees in both cases. Summer fertilized trees had greater leaf biomass than spring fertilized trees. Fibrous root weight was 1.9-fold higher in sandy than in loamy soil. At the end of the cycle, tree N recovery from spring application was 45.7% for sandy and 37.7% for loamy soil; from summer fertilization, N recovery was 58.9% and 51.5% for sandy and loamy soils, respectively. The 15N recovered in the inorganic soil fraction (0?C90?cm) was higher for loamy (1.3%) than for sandy soil (0.4%). Fertilizer N immobilized in the organic matter was lower in sandy (2.5%) than in loamy soil (6.0%). Potential nitrate leaching from fertilizer (15NO 3 ? ?CN in the 90?C110-cm soil layer plus 15NO 3 ? ?CN in drainage water) was 34.8% higher in sandy than in loamy soil. The low N levels in sandy soil resulted from both higher NO 3 ? ?CN leaching losses and higher N uptake of plants grown in the former. The great root mass and higher soil temperatures could account for raised plant N uptake in sandy soil and in summer, respectively. 相似文献
104.
Valero D Díaz-Mula HM Zapata PJ Castillo S Guillén F Martínez-Romero D Serrano M 《Journal of agricultural and food chemistry》2011,59(10):5483-5489
Sweet cherry cultivars ('Cristalina' and 'Prime Giant') harvested at commercial ripening stage were treated with salicylic acid (SA), acetylsalicylic acid (ASA) or oxalic acid (OA) at 1 mM and then stored for 20 days under cold temperature. Results showed that all treatments delayed the postharvest ripening process, manifested by lower acidity, color changes and firmness losses, and maintained quality attributes for longer periods than controls. In addition, total phenolics, anthocyanins and antioxidant activity increased in untreated fruit during the first 10 days of storage and then decreased, while in fruits of all treatments, these parameters increased continuously during storage without significant differences among treatments. Thus, postharvest treatments with natural compounds, such as SA, ASA or OA, could be innovative tools to extend the storability of sweet cherry with higher content of bioactive compounds and antioxidant activity as compared with control fruits. 相似文献
105.
Tarradas J Álvarez B Fraile L Rosell R Muñoz M Galindo-Cardiel I Domingo M Dominguez J Ezquerra A Sobrino F Ganges L 《Veterinary immunology and immunopathology》2011,142(3-4):243-251
The objective of this work was to explore whether a plasmid expressing CCL20 chemokine could improve the immune response against CSFV in co-administration with a DNA vaccine expressing the E2 protein. The immunization of pigs with the DNA vaccine formulation, that contains swine CCL20 chemokine, resulted in the homogenous induction of detectable levels of CSFV antibodies at 36 days after the first injection. Remarkably, immunized animals with E2 DNA vaccine in co-administration with the plasmid containing swine CCL20 developed high titers of neutralizing antibodies against homologous and heterologous CSFV strains and were totally protected upon a lethal viral challenge (sterilizing protection). Our results confirm the role of CCL20 to increase antibody-mediated responses. At the same time suggest the ability of CCL20 to enhance the T helper cell response associated with the induction of neutralizing antibodies against CSFV in pigs previously reported. Systemic replication of virulent CSFV in vivo during the acute phase of infection induces type I IFN. Lower average values of IFN alpha were detected in the serum of pigs immunized with pE2 and pCCL20 at 3 days after challenge. The levels of IFN-alpha detected in pigs immunized with pE2 and principally in non-vaccinated challenged animals can be related to viral load in serum at 3 and 7 days post infection and the clinical signs observed. Our results emphasized the capacity of swine CCL20 chemokine to enhance cellular, humoral and anti viral response with an adjuvant effect in the immune response elicited by E2-DNA vaccination against CSFV. To our knowledge, this is the first report demonstrating the adjuvant effect of swine CCL20 to effectively enhance the potential of DNA vaccine in the immune induction and protection against virus challenge in swine infection model. 相似文献
106.
Carpenter KE Abrar M Aeby G Aronson RB Banks S Bruckner A Chiriboga A Cortés J Delbeek JC Devantier L Edgar GJ Edwards AJ Fenner D Guzmán HM Hoeksema BW Hodgson G Johan O Licuanan WY Livingstone SR Lovell ER Moore JA Obura DO Ochavillo D Polidoro BA Precht WF Quibilan MC Reboton C Richards ZT Rogers AD Sanciangco J Sheppard A Sheppard C Smith J Stuart S Turak E Veron JE Wallace C Weil E Wood E 《Science (New York, N.Y.)》2008,321(5888):560-563
The conservation status of 845 zooxanthellate reef-building coral species was assessed by using International Union for Conservation of Nature Red List Criteria. Of the 704 species that could be assigned conservation status, 32.8% are in categories with elevated risk of extinction. Declines in abundance are associated with bleaching and diseases driven by elevated sea surface temperatures, with extinction risk further exacerbated by local-scale anthropogenic disturbances. The proportion of corals threatened with extinction has increased dramatically in recent decades and exceeds that of most terrestrial groups. The Caribbean has the largest proportion of corals in high extinction risk categories, whereas the Coral Triangle (western Pacific) has the highest proportion of species in all categories of elevated extinction risk. Our results emphasize the widespread plight of coral reefs and the urgent need to enact conservation measures. 相似文献
107.
Peguero-Pina JJ Sancho-Knapik D Cochard H Barredo G Villarroya D Gil-Pelegrín E 《Tree physiology》2011,31(10):1067-1075
Abies alba and Abies pinsapo are two closely related fir species that occur in the Iberian Peninsula under very different environmental conditions. Abies alba proliferates in the humid European mountains, including the Spanish Pyrenees. In contrast, A. pinsapo is a relict species that occurs in some restricted areas of the Mediterranean mountain ranges in Spain and Morocco, which experience intense summer drought periods. To cope with the high atmospheric evaporative demand during summer, A. pinsapo may either have a high resistance to xylem cavitation or develop a very efficient conducting system to reduce the soil-to-leaf water potential gradient. To investigate such hypotheses, we measured (i) the xylem vulnerability to cavitation for different populations, and (ii) several anatomical and hydraulic parameters indicating xylem sufficiency for -supplying water to the shoot in two contrasting populations of both species. Our results show that the resistance to cavitation was not different between species or populations. However, hydraulic conductivity (K(h)), specific hydraulic conductivity (K(s)), leaf-specific conductivity (LSC) and whole-shoot hydraulic conductance (K(shoot)) were higher in A. pinsapo, indicating a higher efficiency of water transport, which should contribute to maintaining its xylem tension below the threshold for rapidly increasing cavitation. The higher K(s) in A. pinsapo was largely a result of its wider tracheids, suggesting that this species may be much more vulnerable to freeze-thaw-induced cavitation than A. alba. This is consistent with the absence of A. pinsapo in northern mountain ranges with cooler winters. These physiological differences could partly explain the niche segregation and the geographical separation of these two firs. 相似文献
108.
Jose?Ignacio?Ruiz?de?GalarretaEmail author Leire?Barandalla Domingo?José?Rios Raquel?Lopez Enrique?Ritter 《Genetic Resources and Crop Evolution》2011,58(3):383-395
Microsatellite markers (SSR) were used to fingerprint a total of 105 local potato cultivars from Spain. A set of 41 cultivars
from Tenerife Island, 19 from the island of La Palma, and 45 local varieties from peninsular Spain were analysed. Some of
these varieties represent relicts of the early introductions originating from South America and have been characterised previously
morphologically and ecophysiologically. We observed within our materials a total of 76 SSR alleles. Only seven of them were
present in all varieties. Several accession and group specific alleles were detected. Similarity coefficients were computed
from the molecular data and cluster analyses were performed. The obtained dendrogram was generally in good agreement with
previous classifications of the accessions as Solanum tuberosum L. subsp. andigena (Juz. et Bukasov) Hawkes S. tuberosum L. subsp. tuberosum and S. chaucha Juz. et Bukasov genotypes. Also cultivar groups with identical or related common names showed the same SSR patterns or clustered
closely together. In addition we performed Principal Coordinate Analysis with the set of genotypes. Results of both analysis
methods were generally in good agreement, but also some smaller differences were detected in the associations of groups and
genotypes. According to the molecular patterns for some accessions misleading or confounded names were evident, and in some
cases the molecular patterns showed also discrepancies with previous species assignments, suggesting the need for a more detailed
comparative study of these accessions. 相似文献
109.
Iglesias DJ Levy Y Gómez-Cadenas A Tadeo FR Primo-Millo E Talon M 《Tree physiology》2004,24(9):1027-1034
We analyzed the effects of nitrate availability on growth of Navelina (Citrus sinensis (L.) Osbeck) scions grafted on three citrus rootstocks differing in salt tolerance: Carrizo citrange (Citrus sinensis (L.) Osbeck x Poncirus trifoliata (L.) Raf.), Citrus macrophylla Wester and Cleopatra mandarin (Citrus reshni Hort. ex Tanaka). Salt stress reduced total plant biomass by 27-38%, whereas potassium nitrate supplementation partially counteracted this effect by increasing dry matter and new leaf area. Salinized Carrizo citrange had the greatest response to nitrate supplementation, whereas the effects on salinized Cleopatra mandarin and C. macrophylla were less apparent. Nitrogen and chlorophyll contents and photosynthetic activity also increased in leaves of the nitrate-supplemented salinized plants. In salinized plants, nitrate supplementation reduced leaf abscission, stimulated photosynthetic activity and increased growth of new leaves. The nitrate treatment did not modify chloride concentration in leaves, but it reduced chloride concentrations in Carrizo and Macrophylla roots. Therefore, in both rootstocks, chloride content was similar in mature leaves, higher in immature leaves and lower in roots of the nitrate-supplemented salinized plants compared with salinized plants unsupplemented with nitrate. We suggest that the nitrate-induced stimulation of growth reduced chloride concentration in roots through the reallocation of chloride to new leaves. 相似文献
110.
This study investigated the possibility of fingerprinting different organic wastes (cow, pig and horse manure) and the vermicomposts produced by different earthworm species (Eisenia andrei, Eudrilus eugeniae and Lumbricus rubellus) analyzing the profiles of fatty acid methyl esters (FAMEs). We found clear differences between their microbial communities, demonstrating the power and sensitivity of the total FAME analysis. In addition, qualitative and quantitative analyses of specific biomarkers permitted to determine differences between samples and to evaluate the effect of earthworms in the decomposition of organic matter. Fatty acid profiles were largely determined by the different vermicomposting earthworm species. Fatty acid 18:2ω6 increased significantly in horse manure vermicomposted by L. rubellus and in cow manure vermicomposted by the three earthworm species, whereas it decreased significantly in pig manure vermicomposted by L. rubellus and E. eugeniae. Fatty acid 20:4ω6 increased significantly in all vermicomposts obtained with the three earthworm species. 相似文献