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61.
We present the concentrations and distribution patterns of nine acid leachable trace metals (ALTMs) Fe, Mn, Cr, Cu, Ni, Co, Pb, Zn, and Cd in the soil samples from the five century old Pachuca-Mineral de Monte mining district of the Central Mexico. The ALTMs do not show any significant correlation with pH, EC, CaCO3, and organic carbon. The metal concentration indicates three distinct distribution patterns. Fe, Mn, Cr, Pb, and Zn show enrichment in the high altitude region of the northern and central part of the study area. Likewise, Cu and Cd are enriched in the northern mountainous terrains. Both these groups show strong positive correlation with Mn indicating that they are associated with Mn-bearing minerals. However, we relate the first group of metals to excessive vehicular transportation and second group to mining waste dumps. The third group of ALTMs Co and Ni indicates its direct relationship to ore processing activities. Comparison of ALTMs concentrations from this study and various other studies throughout the world suggests the need to take precautionary measures of surface soil in high altitude areas to avoid metal enrichments and its subsequent environmental problems. 相似文献
62.
The prevalence of Cryptosporidium in calves and the test properties of six diagnostic assays (microscopy (ME), an immunofluorescence assay (IFA), two ELISA and two PCR assays) were estimated using Bayesian analysis. In a first Bayesian approach, the test results of the four conventional techniques were used: ME, IFA and two ELISA. This four-test approach estimated that the calf prevalence was 17% (95% Probability Interval (PI): 0.1-0.28) and that the specificity estimates of the IFA and ELISA were high compared to ME. A six-test Bayesian model was developed using the test results of the 4 conventional assays and 2 PCR assays, resulting in a higher calf prevalence estimate (58% with a 95% PI: 0.5-0.66) and in a different test evaluation: the sensitivity estimates of the conventional techniques decreased in the six-test approach, due to the inclusion of two PCR assays with a higher sensitivity compared to the conventional techniques. The specificity estimates of these conventional assays were comparable in the four-test and six-test approach. These results both illustrate the potential and the pitfalls of a Bayesian analysis in estimating prevalence and test characteristics, since posterior estimates are variables depending both on the data at hand and prior information included in the analysis. The need for sensitive diagnostic assays in epidemiological studies is demonstrated, especially for the identification of subclinically infected animals since the PCR assays identify these animals with reduced oocyst excretion, which the conventional techniques fail to identify. 相似文献
63.
The need of a combination of animal treatment and environmental measures against a natural Giardia infection in calves between the age of 1 and 6 months was emphasized and evaluated. Ten commercial farms with a total of 94 calves suffering from chronic diarrhea, ill thriving and impaired growth, were included in two subsequent studies. The first study indicated that treatment of all animals with fenbendazole at 15 mg/kg during 3 consecutive days combined with environmental measures on the final day of treatment, which were either removal of bedding, thorough cleaning and ammonia 10% disinfection or relocation of the treated animals to a Giardia free environment, resulted in a total reduction in cyst excretion for at least 2 weeks. In the second study, the immunofluorescence assay (Merifluor Cryptosporidium/Giardia; Meridian Diagnostics Inc., Cincinnati, Ohio) was used quantitatively and confirmed that the combination of treatment and environmental measures resulted in a total reduction of cyst excretion during 2 weeks and in a significant (P<0.05; >or=98.0%) reduction of the cyst excretion until at least 4 weeks after treatment. Furthermore, there was a noticeable improvement of the clinical symptoms in all animals towards day 28 after treatment and 4 months after treatment health in all calves was normal. 相似文献
64.
Shahnoza Hazratkulova Ram C. Sharma Safar Alikulov Sarvar Islomov Tulkin Yuldashev Zafar Ziyaev Zakir Khalikulov Zokhid Ziyadullaev Jozef Turok 《Plant Breeding》2012,131(6):716-721
Normalized difference vegetation index (NDVI), which is a measure of leaf greenness (chlorophyll content), is considered to be correlated with crop productivity. This study was conducted to examine genotypic variations for NDVI at different growth stages and its relationship to yield in winter wheat under terminal heat stress. Thirty winter wheat genotypes were evaluated at two locations in 2009–2010 and 2010–2011 in Uzbekistan. The NDVI was recorded at booting, heading, milk and dough stages. The wheat genotypes differed significantly for NDVI at each stage. Grain yield ranged from 3.9 to 6.1 t/ha. Wheat genotypes differed in per cent decline in NDVI from booting to dough stage. However, several high‐yielding genotypes maintained higher NDVI than low‐yielding genotypes when heat stress was evident. The findings suggest change in NDVI during heat stress could be a measure of tolerance. The positive correlation of NDVI with grain yield suggests that it could be used as an indirect selection criterion for identifying physiologically superior, high‐yielding wheat lines under terminal heat stress. 相似文献
65.
Recent plant diversity changes on Europe's mountain summits 总被引:2,自引:0,他引:2
Pauli H Gottfried M Dullinger S Abdaladze O Akhalkatsi M Benito Alonso JL Coldea G Dick J Erschbamer B Fernández Calzado R Ghosn D Holten JI Kanka R Kazakis G Kollár J Larsson P Moiseev P Moiseev D Molau U Molero Mesa J Nagy L Pelino G Puşcaş M Rossi G Stanisci A Syverhuset AO Theurillat JP Tomaselli M Unterluggauer P Villar L Vittoz P Grabherr G 《Science (New York, N.Y.)》2012,336(6079):353-355
In mountainous regions, climate warming is expected to shift species' ranges to higher altitudes. Evidence for such shifts is still mostly from revisitations of historical sites. We present recent (2001 to 2008) changes in vascular plant species richness observed in a standardized monitoring network across Europe's major mountain ranges. Species have moved upslope on average. However, these shifts had opposite effects on the summit floras' species richness in boreal-temperate mountain regions (+3.9 species on average) and Mediterranean mountain regions (-1.4 species), probably because recent climatic trends have decreased the availability of water in the European south. Because Mediterranean mountains are particularly rich in endemic species, a continuation of these trends might shrink the European mountain flora, despite an average increase in summit species richness across the region. 相似文献
66.
Phenylalanine ammonia-lyase activity (PAL, EC 4.3.1.5), total phenolics, soluble proteins, malondialdehyde and metals accumulation in four-week old chamomile (Matricaria chamomilla) plants cultivated in nutrient solution and exposed to low (3 μM) and high (60 and 120 μM) levels of cadmium (Cd) or copper (Cu) for 7 days were studied. High Cd concentrations had a stimulatory effect on PAL activity and soluble phenolics accumulation while high Cu doses decreased soluble proteins in the leaf rosettes. In the roots, extreme stimulatory effects of 60 and 120 μM Cu were observed on PAL activity, phenolics and malondialdehyde accumulation, while protein content was reduced by these Cu doses. Cd accumulation was higher in the leaf rosettes compared to copper, but the opposite was recorded in the roots. Taken together, the stimulatory effect of Cu on phenolic metabolism was recorded, even though high malondialdehyde accumulation may be an indication that phenolics was not sufficient to counteract reactive oxygen species formation thus leading to damage of membrane integrity. In comparison to Cd, Cu had more noticeable effect on the parameters studied to support its strong redox-active properties. These facts in correlation to antioxidative properties of phenolic metabolites are also discussed. 相似文献
67.
Jozef M. Pacyna 《Water, air, and soil pollution》1986,30(3-4):825-835
Measured air concentrations of several trace elements in southern Scandinavia have been related to long range transport and emissions of the same elements from sources in Europe using receptor modelling and statistical trajectory sector analysis. A good agreement, within a factor of 1.5 between estimates and measurements, has been obtained for Mn, Ni, Cu, and As. Significant differences were noted for V and Pb. 相似文献
68.
Tree species selection for land rehabilitation in Ethiopia: from fragmented knowledge to an integrated multi-criteria decision approach 总被引:1,自引:1,他引:0
Bert Reubens Clara Moeremans Jean Poesen Jan Nyssen Sarah Tewoldeberhan Steve Franzel Jozef Deckers Caleb Orwa Bart Muys 《Agroforestry Systems》2011,82(3):303-330
Dryland regions worldwide are increasingly suffering from losses of soil and biodiversity as a consequence of land degradation.
Integrated conservation, rehabilitation and community-based management of natural resources are therefore of vital importance.
Local planting efforts should focus on species performing a wide range of functions. Too often however, unsuitable tree species
are planted when both ecological suitability for the targeted area or preferences of local stakeholders are not properly taken
into account during selection. To develop a decision support tool for multi-purpose species selection, first information needs
to be pooled on species-specific ranges, characteristics and functions for a set of potentially valuable species. In this
study such database has been developed for the highly degraded northern Ethiopian highlands, using a unique combination of
information sources, and with particular attention for local ecological knowledge and preferences. A set of candidate tree
species and potentially relevant criteria, a flexible input database with species performance scores upon these criteria,
and a ready-to-use multi-criteria decision support tool are presented. Two examples of species selection under different scenarios
have been worked out in detail, with highest scores obtained for Cordia africana and Dodonaea angustifolia, as well as Eucalyptus spp., Acacia abyssinica, Acacia saligna, Olea europaea and Faidherbia albida. Sensitivity to criteria weights, and reliability and lack of knowledge on particular species attributes remain constraints
towards applicability, particularly when many species are jointly evaluated. Nonetheless, the amount and diversity of the
knowledge pooled in the presented database is high, covering 91 species and 45 attributes. 相似文献
69.
Findoráková Lenka Šestinová Oľga Matik Marek Hančuľák Jozef Bureš Radovan 《Journal of Soils and Sediments》2022,22(9):2448-2458
Journal of Soils and Sediments - To evaluate the ecological risk, physico-chemical properties, and the impact of anthropogenic sources on permanent eighteen samples of grass vegetation soils (PGVS)... 相似文献
70.