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71.
M. Wiesmeier D. P. Dick C. Rumpel R. S. D. Dalmolin A. Hilscher & H. Knicker 《European Journal of Soil Science》2009,60(3):347-359
Establishment of pine (Pinus spp.) plantations on grasslands could increase carbon (C) sequestration to counteract increased atmospheric carbon dioxide concentrations. In the grasslands of the southern Brazilian highland (Campos), large areas have been converted to Pinus plantations over the last 30 years. In order to assess the impact of this land‐use change on the amount and composition of soil organic matter (SOM), we investigated a grassland pasture site (G), and both an 8‐year‐old (P8) and a 30‐year‐old (P30) plantation with Pinus taeda. Soil samples down to 45 cm were analysed for texture, pH, soil organic carbon (SOC) and total nitrogen (Ntot) concentrations. Chemical composition of SOM was determined by using cross‐polarization magic angle spinning (CPMAS) 13C NMR spectroscopy. We analysed for stable C isotope (δ13C) and assessed the lignin composition by CuO oxidation. Additionally, contents of pyrogenic organic material (PyOM) were determined because the Campos is regularly burnt. Both pine plantations revealed relatively small SOC concentrations in the mineral soil of 72.6 mg g?1 (P8) and 56.8 mg g?1 (P30) and Ntot concentrations of 4.0 mg g?1 (P8) and 2.9 mg g?1 (P30) for the A horizon, while grassland showed significantly (P < 0.01) larger contents of 100.2 mg g?1 for SOC and 5.9 mg g?1 for Ntot. Accumulation of litter layers suggests decreased input of organic material into the mineral soil under pine, which was confirmed by the δ13C values and lignin composition. Smaller contents of vanillyl‐ (V), syringyl‐ (S), and cinnamyl (C)‐phenols, smaller ratios of S/V and C/V, and smaller ratios of acidic to aldehydic forms of V and S phenols indicated a high degree of decomposition of residual grass‐derived SOM in the upper part of the mineral soil (0–10 cm) under pine plantations. This was confirmed by CPMAS 13C NMR spectroscopy, showing an increasing Alkyl C/O‐Alkyl C ratio at the same depth. No significant changes in the contents of PyOM could be detected, but all sites tended to show the greatest concentrations at deeper soil depths > 15 cm, indicating a vertical relocation of PyOM. The results suggest that decomposition of residual SOM originating from grassland species contributes to the decrease of SOC and Ntot and to an acidification in the topsoil under pine plantations. We also suggest that slow litter decomposition and incorporation and the absence of fires at the plantations are additional reasons for the reduced amount of SOM. Depletion of SOM and the acidification of the topsoil may reduce the availability and supply of nutrients and diminish the C sequestration potential of the mineral soil. 相似文献
72.
In this study we investigated the quantitative and qualitative aspects of soil organic matter (SOM) losses caused by water erosion within a small catchment in Northern Laos, under steep slopes and slash and burn agriculture. The soils in the region have a high contribution of black carbon to soil organic matter and high erosion rates. The aim of the study was to quantify the erosion of black carbon and to identify the processes involved. The conceptual approach included the measurement of contents of SOM, black carbon and mineral bound SOM in bulk soils, sediments eroded from 1 m2 plots and in sediments at the outlet of the 0.6 ha catchment. Additionally, the enrichment factors of bulk SOM, BC and mineral bound SOM were calculated for eroded sediments. 相似文献
73.
Fingerprinting sediment sources in the outlet reservoir of a hilly cultivated catchment in Tunisia 总被引:1,自引:1,他引:1
Abir Ben Slimane Damien Raclot Olivier Evrard Mustapha Sanaa Irène Lefèvre Mehdi Ahmadi Mouna Tounsi Cornelia Rumpel Abdallah Ben Mammou Yves Le Bissonnais 《Journal of Soils and Sediments》2013,13(4):801-815
Purpose
Approximately 74 % of agricultural soils in Tunisia are affected by water erosion, leading to the siltation of numerous human-made reservoirs and therefore a loss of water storage capacity. The objective of this study was to propose a methodology for estimating the relative contributions of gully/channel bank erosion and surface topsoil erosion to the sediment accumulated in small reservoirs.Materials and methods
We tested an approach based on the sediment fingerprinting technique for sediments collected from a reservoir (which has been in operation since 1994) at the outlet of a catchment (Kamech, 2.63 km2). Sampling concentrated on the soil surface (in both cropland and grassland), gullies and channel banks. A total of 17 sediment cores were collected along a longitudinal transect of the Kamech reservoir to investigate the origin of the sediment throughout the reservoir. Radionuclides (particularly caesium-137, 137Cs) and nutrients (total phosphorus, total nitrogen and total organic carbon (TOC)) were analysed as potential tracers.Results and discussion
The applications of a mixing model with 137Cs alone or 137Cs and TOC provided very similar results: The dominant source of sediment was surface erosion, which was responsible for 80 % of the total erosion within the Kamech catchment. Additionally, we showed that the analysis of a single composite core provided information on the sediment origin that was consistent with the analysis of all sediment layers in the core. We demonstrated the importance of the core sampling location within the reservoir for obtaining reliable information regarding sediment sources and the dominant erosion processes.Conclusions
The dominance of surface erosion processes indicates that conservation farming practices are required to mitigate erosion in the agricultural Kamech catchment. Based on the results from 17 sediment cores, guidelines regarding the number and location of sampling cores to be collected for sediment fingerprinting are proposed. We showed that the collection of two cores limited the sediment source apportionment uncertainty due to the core sampling scheme to <10 %. 相似文献74.
Walter W. WENZEL Cornelia MESMER Eric J. FLORIDA Markus PUSCHENREITER Holger KIRCHMANN 《土壤圈》2022,32(4):543-554
Diffusive gradients in thin films (DGT) measurements have been shown to outperform other phosphorus (P) tests in soils with strong P sorption, but this has not been confirmed for moderately weathered European soils. We compared the performance of DGT in predicting wheat grain yield in Swedish long-term fertility experiments with those of standard intensity (water-extractable P (P-H2O)) and quantity (ammonium lactate-extractable P (P-AL)) tests. A Mitscherlich-type model was used to fit wheat yield response to P application rates (0, 15, 30 or 35, and 45 kg P ha-1 year-1) in each individual trial replicate to estimate the maximum yield. For trials with clear plateau-type yield responses and the goodness of fit (R2) > 0.75, relative yields (RYs) were calculated for each P treatment and plotted against the soil P test results (n=143). The goodness of the Mitscherlich-type fits decreased in the following order:DGT-measured P (P-DGT) (R2=0.35) > P-H2O (R2=0.18) > P-AL (R2=0.13). When excluding soils with P-AL:P-DGT ≥ 0.1 L g-1, R2 was considerably improved to 0.55 for P-AL, 0.46 for P-H2O, and 0.65 for P-DGT (n=61). At 95% of maximum yield, the upper limit of P deficiency for P-DGT was 44.8 (the soils with P-AL:P-DGT < 0.1 L g-1) and 61.9 μg L-1 (all soils), falling within the range reported for other European and Australian soils (6.0-142 μg L-1). We show that in the investigated Swedish soils, DGT performed better than the quantity and intensity tests, which is attributed to its ability to capture P diffusion and resupply from the soil solid phase, similar to plant roots in the rhizosphere. 相似文献
75.
76.
77.
Cornelia Adlhoch Aleksandra Miteva Anna Zdravkova Tihana Miki Draen Kneevic Sokratis Perdikaris Krzysztof
mietanka Edyta
wito Vilem Kopriva Martin Chudý Luis Jose Romero Gonzlez Ines Moreno Gil Annica Walln Norell Frank Verdonck 《Zoonoses and public health》2019,66(7):874-878
We estimated that more than 11,000 people were exposed to highly pathogenic avian influenza viruses in EU/EEA countries over the outbreak period October 2016–September 2018 by cross‐linking data submitted by Member States to European Food Safety Authority and EMPRES‐i. A stronger framework for collecting human exposure data is required. 相似文献
78.
Hematologic reference intervals for Xenopus tropicalis with partial use of automatic counting methods and reliability of long‐term stored samples
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79.
Heather Fenton María J. Forzán Marion Desmarchelier Meghan Woodland Soraya Sayi Cornelia V. Gilroy 《The Canadian veterinary journal. La revue veterinaire canadienne》2016,57(1):80-83
A 3-year-old female gerbil developed a non-healing skin wound due to a malignant neoplasm. Histology, immunohistochemistry (cytokeratin 19 positive; vimentin, estrogen, and progesterone receptor negative), and electron microscopy (no desmosomes or melanosomes) revealed an undifferentiated carcinoma with pulmonary metastasis. Unlike in previous reports, it did not arise from the abdominal pad’s sebaceous gland. 相似文献
80.
Ruth Müller Cornelia Bandow Anne Seeland Dennis Fennel Anja Coors Peter K. Ebke Bernhard Förster Pedro Martinez-Arbizu Thomas Moser Matthias Oetken Jasmin Renz Jörg Römbke Nadine Schulz Jörg Oehlmann 《Journal of Soils and Sediments》2010,10(4):718-721