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101.
Kleinschmidt S Meneses F Nolte I Hewicker-Trautwein M 《Veterinary immunology and immunopathology》2007,120(3-4):80-92
It has been suggested but not proven that hypersensitivity type I reactions are involved in the pathogenesis of canine inflammatory bowel disease (IBD). The main effector cells in type I hypersensitivity reactions are mast cells (MCs). Canine MCs, as human MCs, can be subdivided into three subtypes according to their content of mast cell-specific proteases: tryptase (MCT), chymase (MCC), or tryptase and chymase bearing MCs (MCTC). In this study, numbers and subsets of mast cells were investigated in biopsies from the gastrointestinal tract of dogs with histopathologically confirmed lymphocytic-plasmacytic enteritis (LPE) (n = 4), lymphocytic-plasmacytic colitis (LPC) (n = 1) and eosinophilic gastroenterocolitis (EGE) (n = 11). Paraffin sections of formalin-fixed samples from the stomach, small intestine (duodenum, jejunum, ileum) and colon were stained by using a metachromatic staining method (kresylecht-violet; KEV) and a combined enzyme histochemical and immunohistochemical technique for chymase and tryptase. Additionally, immunohistochemistry with antibodies against T cells (CD3), macrophages (myeloid/histiocyte antigen) and IgA, IgG and IgM bearing cells was conducted. Quantitative evaluation of mast cells and semiquantitative scoring of immunohistochemically stained cells were performed. Between the two histopathologically defined groups clear differences concerning mast cell numbers were detected. In most affected intestinal tissue locations of dogs with LPE/LPC a decrease in metachromatically (kresylecht-violet) stained granule-containing MCs and immunohistochemically stained MCT,C,TC was found. This reduction could be due to mast cell degranulation, a T helper cell 1 dominated reaction pattern or a “thinning out” due to increasing T cells, IgA and IgG bearing cells. Dogs with EGE displayed higher variability in mast cell numbers but most of the affected large and small intestinal locations had increased numbers of MCs. In these cases, T cells, IgA bearing cells and macrophages also increased. Increased numbers of MCs and eosinophils seen in the intestinal mucosa of dogs with EGE could indicate the presence of a type I hypersensitivity reaction (T helper cell 2 pattern) in response to dietary antigens. Changes in cell numbers occurred also in unaffected locations of dogs with LPE/LPC and EGE which showed reduced MCT,C,TC, increased KEV positive cells and partially increased leucocytes and macrophages. 相似文献
102.
Axel Gzik Matthias Kuehling Ingo Schneider Bernd Tschochner 《Journal of Soils and Sediments》2003,3(1):29-34
In soils, animals and plants from selected sites in the Rustenburg mining area, a part of the South African ore belt, the
heavy metal burden was examined. These sites belong to different soil types and are characterized by different land-use (agriculture,
grassland). The heavy metal contamination of the soil samples is relatively high and is dominated by chromium and nickel,
metals, which are extracted in the mine near the sampling sites. These high heavy metal concentrations had no clear inhibitory
influence on micro-organisms or the enzyme activity of soils. It appears that the high clay content of the soils may counteract
the influence of heavy metals. On the other hand, tolerant microbial populations may have been established. In addition, the
investigated culture plants there was no correlation between the heavy metal content of the soils and the concentrations in
roots and shoots. The dangerous, potential contamination of organs in humans seems to be modest, with the exception of tobacco
leaves. The heavy metal content of tissues in the examined animals reflect the environmental habitat in situ with no obvious
influence on the health of the animals. 相似文献
103.
In continuation of earlier work, the results of field scale - regularly as well as randomly distributed - and regional randomly distributed measurements of relative gas diffusion coefficients are presented for loess soils in dependence of the gas filled relative pore space ?. Maps are shown for the field distribution variables both, Ds/Da and ?. The maps show more homogeneous regions within the already relatively homogeneous field. - When compared with linear and power regression, all Ds/Da (?) measurements show lowest standard deviations using exponential regression. This is in contradiction to nearly all the Ds/Da (?) measured elsewhere. The reason for this may be explained by the technique of measurement used. In this context, the physical meaningfulness of this exponential regression is discussed. An example is also given, moreover, how sensitively Ds/Da (?) may demonstrate differences in soil structure induced by tillage practizes. 相似文献
104.
Ingo Whler Stefan Klaß Manigee Derakshani Gerold Stellmacher Jrg-Ulrich Winter Werner Reißer 《植物养料与土壤学杂志》1998,161(1):31-34
The occurrence of terrestrial algae on two beech sites was determined qualitatively and quantitatively in the litter, organic and mineral layer. Both sites are beech stands of different age and the soil type is a Cambisol. On the site with young beech the maximal value determined was 1.0 · 108 algae g?1 dw in the litter layer. With increasing soil depth the number of algae decreased on both sites, and at the young beech stand site no algae were found in the mineral soil. Chlorophyceae were the dominant algae group and at the young beech stand Bacillariophyceae were present. 相似文献
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108.
The fracture behaviour of single wood fibres is governed by geometrical constraints: in situ ESEM studies on three fibre types 总被引:1,自引:1,他引:0
In situ tensile tests were performed in an environmental scanning electron microscope (ESEM) on earlywood, transition wood
and latewood cells of Norway spruce (Picea abies [L.] Karst.). In order to examine the single wood fibres in a wet state, a specially designed tensile testing stage with
a cooling device was built. The fracture behaviour of the cell types was studied at high resolution while straining. Different
failure mechanisms were observed for the three tissue types. The thin-walled earlywood fibres showed tension buckling which
gave rise to crack initiation and resulted in low tensile strength, whereas thick-walled latewood fibres predominately failed
by transverse crack propagation without fibre folding. 相似文献
109.
110.
The role of soil chemical properties,land use and plant diversity for microbial phosphorus in forest and grassland soils
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Elisabeth Sorkau Steffen Boch Runa S. Boeddinghaus Michael Bonkowski Markus Fischer Ellen Kandeler Valentin H. Klaus Till Kleinebecker Sven Marhan Jörg Müller Daniel Prati Ingo Schöning Marion Schrumpf Jan Weinert Yvonne Oelmann 《植物养料与土壤学杂志》2018,181(2):185-197
Management intensity modifies soil properties, e.g., organic carbon (Corg) concentrations and soil pH with potential feedbacks on plant diversity. These changes might influence microbial P concentrations (Pmic) in soil representing an important component of the P cycle. Our objectives were to elucidate whether abiotic and biotic variables controlling Pmic concentrations in soil are the same for forests and grasslands, and to assess the effect of region and management on Pmic concentrations in forest and grassland soils as mediated by the controlling variables. In three regions of Germany, Schwäbische Alb, Hanich‐Dün, and Schorfheide‐Chorin, we studied forest and grassland plots (each n = 150) differing in plant diversity and land‐use intensity. In contrast to controls of microbial biomass carbon (Cmic), Pmic was strongly influenced by soil pH, which in turn affected phosphorus (P) availability and thus microbial P uptake in forest and grassland soils. Furthermore, Pmic concentrations in forest and grassland soils increased with increasing plant diversity. Using structural equation models, we could show that soil Corg is the profound driver of plant diversity effects on Pmic in grasslands. For both forest and grassland, we found regional differences in Pmic attributable to differing environmental conditions (pH, soil moisture). Forest management and tree species showed no effect on Pmic due to a lack of effects on controlling variables (e.g., Corg). We also did not find management effects in grassland soils which might be caused by either compensation of differently directed effects across sites or by legacy effects of former fertilization constraining the relevance of actual practices. We conclude that variables controlling Pmic or Cmic in soil differ in part and that regional differences in controlling variables are more important for Pmic in soil than those induced by management. 相似文献