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231.
The Australian psyllid Ctenarytaina eucalypti has been accidentally introduced into many parts of the world. In America as well as in Europe it caused severe damage on Eucalyptus cut-foliage plantations. Insecticide treatments have proven to be expensive and not-sustainable. Therefore a biocontrol project was carried out in the Center for Biological Control at Berkely, California. The search for a monophagous parasitoid of the blue gum psyllid in the natural habitat in Australia and New Zealand was successful. After quarantine for elimination of hyperparasitoids the natural enemy Psyllaephagus pilosus has been released in Californian Eucalyptus plantations since 1993. It established itself rapidly, resulting in a decrease of the pest below the economic threshold. Following this impressive effect the parasitoid has also been released in some West European countries. The rapid spread over great territories was similar. The parasitization rates reached 100 percent, providing a sustainable control of the psyllid. In the last years several accidental introductions of C. eucalypti into Germany occurred. The first record in Saxony was in 2000 in the botanical garden of the Dresden University of Technology on Eucalyptus globulus. However, the spontaneous attack of the blue gum psyllid by P. pilosus during the next two years eradicated the infestation. To avoid a possible threat to natural ecosystems, the well-directed future use of exotic biological control agents against unintentionally introduced pests is in urgent need of a legal regulation at the EU or national level in Germany. The FAO and EPPO standards on this topic should be considered as a basis for this. 相似文献
232.
Freeman L. McEwen Gwen Ritcey Heinz Braun Richard Frank Brian D. Ripley 《Pest management science》1980,11(6):643-650
Residues were determined at 8-h intervals during the 48 h after application of endosulfan, leptophos, methamidophos, methomyl and mevinphos to head lettuce; of endosulfan, methamidophos and methomyl to cauliflower; and of parathion to onions and carrots. Residues of phosalone and parathion were measured on apple leaves 0, 1, 2, 4, 8 and 16 days after application. In addition, the portion of the residue on apple leaves that could be dislodged was measured, as well as the residues on gloves used to handle the apple foliage. There were large differences in the rates of disappearance of the insecticides, differences that must be known in determining safe re-entry periods for workers. 相似文献
233.
According to the electron microscopic investigations the most evident sign of the phase of the active involution of the mammary gland in cattle is the occurrence of different great vacuoles with a diffuse content in the cytoplasma of the secretory cells till the 30th day after the beginning of the dry period. Secretory cells which go over in the rest phase show a great reduction of the cell organelles and many filaments and secondary lysosomes or residual bodies. One can observe many macrophages and lymphocytes in the partly enlarged intercellular rooms between the secretory cells and the myoepithelial cells. The myoepithelial cells are adapting to the changing forms of alveoli. The phase of the colostrogenesis is characterised by the enlargement of the cell organelles and the reappearance of vacuoles. 相似文献
234.
It was found that different procedures of heat treatment influenced the true digestibility of nitrogen and of the amino acids in cereals. In view of the fact that under practical feeding conditions pelleting is the most widely used procedure studies were made in trials with young pigs fed coarsely ground barley or maize of pellets of these as sole diet. 相似文献
235.
Carl Fedtke Brigitte Depka Otto Schallner Klaus Tietjen Achim Trebst Detlef Wollweber Heinz‐Jürgen Wroblowsky 《Pest management science》2001,57(3):278-282
The new bleaching herbicidal compound N,N‐diethyl‐N‐(2‐undecynyl)amine (NDUA) is identified here as an inhibitor of lycopene cyclase and is compared with the known cyclase inhibitors N,N‐diethyl‐N‐[2‐(4‐chlorophenylthio)ethyl]amine (CPTA) and N,N‐diethyl‐N‐[2‐(4‐methylphenoxy)ethyl]amine (MTPA). HPLC separation of chloroplast pigments shows lycopene accumulation in NDUA treated tissue. Variation in chain length of the undecynylamine moeity of NDUA from 7 to 21 C atoms reveals an optimum of 11 to 14 C atoms for herbicidal activity. A series of seven further analogues of NDUA and CPTA reveals the structural elements necessary for inhibition of lycopene cyclase. The effect of NDUA derivatives on photosynthesis has been studied in Chlamydomonas reinhardtii. Photosynthesis is highly sensitive, particularly towards the C14 and longer chain length analogues at nanomolar concentrations. It is shown that the breakdown of photosynthesis by NDUA is due to interference with the turnover of the D1 protein of the photosystem II reaction centre that requires the continous biosynthesis of the two reaction‐centre β‐carotene moieties in the reassembly phase. The D1 protein disappearance is most marked under strong light conditions. The depletion of photosystem II occurs before total pigment bleaching. This newly recognized mechanism in herbicidal activity is also the basis for the mode of action of other lycopene cyclase inhibitors as well as phytoene desaturase inhibitors. © 2001 Society of Chemical Industry 相似文献
236.
John Kormla Nyameasem Reiner Ruser Christof Kluß Christoph Essich Mareike Zutz Martin ten Huf Caroline Buchen-Tschiskale Heinz Flessa Hans-Werner Olfs Friedhelm Taube Thorsten Reinsch 《Grass and Forage Science》2023,78(3):338-358
The effect of slurry application techniques and slurry N stabilizing strategies on nitrous oxide emission from grasslands is poorly understood and, therefore, can result in large uncertainties in national/regional inventories. Field experiments were, thus, conducted to estimate the effect of different fertilization techniques on nitrous oxide (N2O) emissions. Fertilizer was applied (135–270 kg N ha−1 year−1) as calcium ammonium nitrate (CAN), untreated or treated cattle slurry. The slurry was either treated with sulfuric acid (target pH = 6.0), applied using trailing shoes or treated with 3,4-dimethyl pyrazole phosphate and applied via slot injection. N2O fluxes were sampled using the closed chamber technique. Cumulative N2O emissions ranged 0.1–2.9 kg N ha−1 year−1 across the treatment, sites and years. The N application techniques showed inconsistent effects on soil mineral N content, cumulative N2O emission and N yield. The fertilizer replacement value of slurry was low due to low N use efficiencies at the sites. However, a close positive relationship (r = 0.5; p = .013) between slurry value and biomass yield was observed, highlighting the benefit of high slurry value on crop productivity. N2O-N emission factors were low for all treatments, including CAN, but were 2–6 times higher in 2019 than in 2020 due to lower precipitation in 2020. Variations in N2O emission were largely explained by soil and climatic factors. Even with the low N2O emissions, this study highlights the benefit (significant mitigation of N2O emissions) of replacing the increasingly expensive chemical fertilizer N with input from slurry under favourable conditions for denitrification. 相似文献
237.
238.
Linda S. Heath Pekka E. Kauppi Peter Burschel Heinz -Detlev Gregor Robert Guderian Gundolf H. Kohlmaier Susanne Lorenz Dieter Overdieck Florian Scholz Harald Thomasius Michael Weber 《Water, air, and soil pollution》1993,70(1-4):55-69
Temperate forests currently cover about 600 MHa, about half of their potential. Almost all these forests have been directly impacted by humans. The total living biomass in trees (including roots) was estimated to contain 33.7 Gt C. The total C pool for the entire forest biome was estimated as 98.8 Gt. The current net sink flux of biomass was calculated at 205 Mt yr?1, with a similar amount removed in harvests for manufacture into various products. The major cause of this C sink is forest regrowth. Forest regrowth is possible because fossil fuels are the major source of energy in temperate countries, instead of fuelwood. Future C in these forests will be greatly influenced by human activity. Options to sequester more C include conservation of forest resources, activities that increase forest productivity such as adopting rotation ages to optimize C production, afforestation, improvement of wood utilization, and waste management. 相似文献
239.
Phosphorus in forest ecosystems: New insights from an ecosystem nutrition perspective 总被引:1,自引:1,他引:1
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240.
Since the mid-1990s, the cultivation of white lupin (Lupinus albus L.) has rapidly decreased in Germany and other countries in Central Europe because of the occurrence of Colletotrichum lupini, the causal agent of the fungal disease anthracnose, and the lack of varieties with a sufficient resistance towards this disease. To reestablish the relevance of cultivating white lupins, the development of new varieties with improved resistance is vital. In the study presented here, new breeding lines were evaluated from 2012 to 2014 on a total of five experimental sites in Germany. In each year, at least on one site a high disease pressure with good differentiation built up from natural seed infestations, so that evaluation and further selection for resistance was possible in all 3 years. The breeding lines showed improved performance of resistance towards C. lupini (anthracnose disease score 3.8 on average of all breeding lines and environments) compared to the reference varieties (anthracnose disease score 5.8). Improved resistance had a favorable effect on grain yield, particularly in environments with high disease pressure, and yield stability. Average grain yields were 2.6 t ha?1 for the breeding lines and 1.5 t ha?1 for the reference cultivars. Among the tested range of white lupins, the breeding material showed consistently higher grain yields on average of all environments compared to the rather low and variable yielding reference cultivars. The alkaloid content varied among environments and breeding lines. 相似文献