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71.
72.
Efficacy of fungicides on Hymenoscyphus fraxineus and their potential for control of ash dieback in forest nurseries 下载免费PDF全文
Twenty‐six commercial formulations of fungicides at six concentrations were evaluated in vitro for their efficacy on mycelial growth of Hymenoscyphus fraxineus (anamorph Chalara fraxinea). The results are presented as EC50, EC90 and minimal inhibitory concentration values; the comparisons with the recommended application concentrations showed that 10 of the 26 fungicides were highly effective in their ability to inhibit the mycelial growth of the pathogen. The eight most effective fungicides identified based on multiple comparisons analysis were azoxystrobin, bitertanol, captan (in two‐component preparation with trifloxystrobin), difenoconazole, kresoxim‐methyl, spiroxamine (in multicomponent preparation with tebuconazole and triadimenol), tebuconazole and trifloxystrobin. Azoxystrobin, difenoconazole, kresoxim‐methyl, mancozeb, myclobutanil, pyrimethanil, tebuconazole and trifloxystrobin were selected to verify their effectiveness in in planta tests. During two field tests in nurseries, it was found out that tebuconazole (triazole), trifloxystrobin and kresoxim‐methyl (strobilurins) and mancozeb (dithiocarbamate) were significantly effective against H. fraxineus. The best results were gained with tebuconazole, when mean percentage of diseased saplings was 16.3%, whereas in the control, it was 63.6%. The combination and alternation of fungicides from the triazole, strobilurine and dithiocarbamate chemical groups should be an effective tool for protecting ash saplings in forest nurseries. Moreover, exact timing of the treatment reflecting rainfall and development of first symptoms in the foliage will be also important. 相似文献
73.
Relationships between available soil water and indicators of plant water status of sweet sorghum to be applied in irrigation scheduling 总被引:3,自引:0,他引:3
Optimal crop production depends greatly on available soil water, and it is therefore important to know when and how much
to irrigate in order to attain agronomic potential. In this work, plant indicators are used to assess water stress. These
are compared with available soil water to find the critical point for irrigation scheduling of sweet sorghum. The experimental
trial was carried out in Bečej, in the Vojvodina region, on a sweet sorghum crop, grown in moderate climatic conditions on
a well-drained, deep chernozemolic meadow soil. Plant indicators tested were predawn and midday leaf water potential and crop
and air temperature difference. All the methods were sensitive to water deficit in plants, but not all can be used for irrigation
scheduling. The predawn leaf water potential was the most reliable parameter among those tested due to its relative independence
from weather conditions and a valid indicator of plant water status. This was not the case with canopy-air temperature difference.
The predawn leaf water potential corelation with available soil water indicates that the threshold value for irrigation scheduling
of sweet sorghum is when the former has decreased to –0.45 MPa. This corresponds to a soil water depletion to about 10% of
available water in the active root zone. The canopy-air temperature difference was sufficiently sensitive to indicate the
onset of mild plant water stress, although it showed a certain threshold value when water shortage appeared, which occurred
when the air and canopy temperature were the same.
Received: 9 April 1996 相似文献
74.
In this study the hydrological regime of Norway spruce (Picea abies) and birch (Betula pendula) growing on heavy soils in the south east of Austria was analysed. Results from the year 2003 characterised by an extremely hot and dry summer are presented in this paper. Due to the extreme weather conditions the soil water content in August 2003 was very low (0.10–0.25 m3 m−3) in the topsoil (0–50 cm) with no explicit difference between both tree species. 相似文献
75.
Three adjacent EcoRI fragments of the rDNA unit from Lycopersicon esculentum, eleven anonymous genomic and two anonymous cDNA
clones from Brassica napus and three restriction endonucleases: BamHI, EcoRI and EcoRV were used for RFLP analysis of the
genome of Hypericum perforatum L. A polymorphic band identified with EcoRI and two rDNA probes in five somaclones originated
from the same genotype was detected in all progenies of two somaclones indicating the inheritance of the molecular changes.
rDNA unit heterogeneity represented by two types of RFLP pattern revealed among somaclones and seed-derived control plants
using EcoRV and two rDNA probes may indicate an alloploid origin of Hypericum perforatum. The occurrence of the identical
RFLP patterns in some R0 somaclones and seed-derived plants and their progenies may be related to the apomictic mode of reproduction which is assumed
to be prevalent in Hypericum perforatum. The differences in RFLP patterns of progenies when compared with the maternal plants
(1 out of 10 progenies of one control plant and 1 out of 8 progenies of one somaclone) may indicate that some progenies have
originated through sexual recombination.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
76.
Karolina Tahovská Petr Čapek Hana Šantrůčková Jiří Kaňa Jiří Kopáček 《Communications in Soil Science and Plant Analysis》2016,47(4):487-494
A hybrid anion resin was tested for in situ phosphorus (P) availability measurement in soils of two stands recovering from acidification and having different P-sorption characteristics. The phosphate (P-PO4) sorption capacity of the resin (before saturation) was 48 µmol g?1. Sorption and elution were tested under P-PO4 concentrations common in acidic soils (0–0.42 mmol l?1) either with or without the presence of sulfate (0.2 mmol l?1). The efficiency of P-PO4 sorption was independent of the sulfate and was 100 ± 0.2% (n = 56, ± SD). The P-PO4 recovery stabilized after six elution steps (each: 50 ml of 0.5 M sodium hydroxide, resin/solution 5:1). The efficiency of P-PO4 recovery was 80 ± 7% and was used to evaluate field measurements. We determined the amount of P-PO4 in the field using resin bags in three consecutive years. The results indicate that bioavailable P is negatively related to the soil ability to retain P. 相似文献
77.
Andrej Simončič Janez Sušin Marjan Šinkovec Robert Leskovšek Franc Čuš Vida Žnidaršič Pongrac 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2017,67(5):381-394
During the period 2004–2015, the upper soil layer (0–20?cm) was sampled in eight agricultural production areas in Slovenia. Overall, 53, 249, 169, 139, and 413 samples were respectively taken from vegetable fields, arable cropland, hop fields, orchards, and vineyards. Copper was measured in the aqua-regia extracts of these samples using flame atomic absorption spectrometry. The minimum, maximum, average, and median concentrations were calculated for five land uses and for all eight production areas in Slovenia. Sample portions below and/or above the limit, warning, and critical concentrations of 60, 100, and 300?mg/kg, respectively, were calculated as well. The results were compared for different land uses and production areas and showed that the copper concentrations in the vegetable, arable crop, and hop fields and orchards did not exceed the critical concentration. In addition, the copper concentrations in the vineyards exceeded the critical concentration but the maximum copper concentration (508?mg/kg) was still lower than the concentrations reported from other vine-growing Mediterranean countries. Also, the copper concentrations in hop fields exhibited an increasing trend in the Celje (and Maribor) area(s). 相似文献
78.
ROBERT LESKOVŠEK AVISHEK DATTA STEVAN Z. KNEZEVIC ANDREJ SIMONČIČ 《Weed Biology and Management》2012,12(2):98-108
Dry matter partitioning and allocation is a major determinant of plant growth and its competitiveness. Common ragweed (Ambrosia artemisiifolia) is a troublesome agronomic weed species and it is also a major health concern in Europe and many other countries because of its rapid spreading and production of allergenic pollen. A field experiment was conducted in 2009 to determine the effect of nitrogen fertilizer levels (0, 100, and 200 kg ha?1) and plant density levels (1.3, 6.6, and 13.2 plants per m2) on the leaf, stem dry matter partitioning, and dry matter allocation of ragweed. With an increasing density, the stem partitioning coefficient increased, whereas the leaf partitioning coefficient decreased. The addition of nitrogen had a limited effect on the leaf and stem dry matter partitioning. The root dry matter production decreased with an increasing density and was not influenced by the addition of nitrogen. Under intraspecific competition, ragweed exhibited a stronger above‐ground competition intensity than below the ground, which resulted in a greater root : shoot ratio, compared to the low‐density stands. The level of nitrogen influenced the vertical leaf, stem, and total dry matter distribution, with a greater allocation to the top stratum of the plants, thus increasing their competition for light. The biomass allocation of ragweed to the roots in response to the nitrogen supply exhibited a low plasticity, compared to the shoots, which displayed a high plasticity. The results of this study suggested that, under intraspecific conditions and with an increasing nitrogen supply, ragweed would be more competitive in above‐ground resource acquisition. 相似文献
79.
Modulation of ruminal and intestinal fermentation by medicinal plants and zinc from different sources 下载免费PDF全文
Zora Váradyová Dominika Mravčáková Monika Holodová Ľubomira Grešáková Jana Pisarčíková Marcin Barszcz Marcin Taciak Anna Tuśnio Svetlana Kišidayová Klaudia Čobanová 《Journal of animal physiology and animal nutrition》2018,102(5):1131-1145
Two experiments were conducted on sheep to determine the effect of dietary supplementation with zinc and a medicinal plant mixture on haematological parameters and microbial activity in the rumen and large intestine. In Experiment 1, 24 male lambs were randomly divided into four groups: One group was fed an unsupplemented basal diet (control), and three groups were fed a diet supplemented with 70 mg Zn/kg diet in the form of Zn sulphate (ZnSO4), a Zn‐chelate of glycine hydrate (Zn‐Gly) or a Zn‐proteinate (Zn‐Pro), for five months. The ruminal content was collected separately from each lamb, and batch cultures of ruminal fluid were incubated in vitro with mixture of medicinal plants (Mix) with different roughage:concentrate ratios (800:200 and 400:600, w/w). Bioactive compounds in Mix were quantified by UPLC/MS/MS. In Experiment 2, four sheep were fed a diet consisting of meadow hay and barley grain (400:600, w/w), with Zn‐Gly (70 mg Zn/kg diet), Mix (10% replacement of meadow hay) or Zn‐Gly and Mix (Zn‐Gly‐Mix) as supplements in a Latin square design. Mix decreased total gas (p < 0.001) and methane (p < 0.01) production in vitro. In Experiment 1, caecal isobutyrate and isovalerate concentrations varied among the dietary treatments (p < 0.01). The isovalerate concentration of the zinc‐supplemented groups in the distal colon was higher (p < 0.001) compared with the control. In Experiment 2, the molar proportion of isobutyrate was the highest in the faeces of the sheep fed the diet with Zn‐Gly‐Mix (p < 0.01). The plasma zinc concentration was higher in the groups fed a diet supplemented with zinc (p < 0.001). The haematological profile and antioxidant status did not differ between the dietary groups (p > 0.05). The diets containing medicinal plants and organic zinc thus helped to modulate the characteristics of fermentation in ruminants. 相似文献
80.