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71.
Influence of long-term slurry application on soil nutrients. 2. Fractions and solubility criteria of soil phosphorus Fractions and solubility criteria of soil phosphorus accumulated by long-term slurry application were investigated. The following results were obtained:
- – Slurry application mainly resulted in higher concents of inorganic phosphorus, especially Fe-Al-P, even in deeper soil layers.
- – The accumulation of inorganic phosphorus resulted in an increase of phosphorus availability in all conventional extraction methods used, as well as in higher phosphorus concentration of the soil solution.
- – In the upper soil layers of luvisols and in the deeper soil layers of diluvial sandy soils organic phosphorus was enriched, but did not significantly influence phosphorus intensity and delivery.
- – Compared to soils supplied with mineral fertilizers there are no particularities in phosphorus dynamics, from which differences in the interpretation of “available” phosphorus values with respect to phosphorus recommendation scales could be concluded.
72.
Preparation and use of 33P labelled carbonate fluorapatite in studies on the effect of phosphate rock containing fertilizers For a precise evaluation of the effectiveness of the different phosphate fractions in partially acidulated phosphate rocks these fractions were alternatively labelled. For this purpose a technique was developed to prepare synthetic, 33P labelled carbonate fluorapatite (francolite type). A labelled (NH4)2HPO4 solution (+ Na2CO3, NH4F) was poured into a Ca(NO3)2 × 4H2O solution (pH 12) and the washed precipitate heated until the aimed solubility was reached (e.g. 2 h 400°C + 1.5 h 600°C). After grinding this mother phosphate rock was acidulated with sulphuric acid to fully acidulated superphosphate and partially acidulated phosphate rock. The nonacidulated rock residue was extracted from the partially acidulated phosphate rock. In an identical procedure phosphate rock was prepared without addition of 33P and in part acidulated to superphosphate. Mixing of labelled phosphate rock and not labelled superphosphate (and vice versa) gave two fertilizer mixtures with alternate labelled fractions equivalent to the fully labelled partially acidulated phosphate rock. Mineralogical properties of the synthetic phosphate fertilizers and their turnover in pot experiments with rye grass were corresponding to that of commercial products. The reactivity of the nonacidulated rock residue was inferior to that of the original phosphate rock after the process of partial acidulation. Fertilizer utilization was determined by use of isotopes (33P) and total P uptake method. P utilization as determined by total P uptake method was significantly higher compared to the real fertilizer effectiveness measured by 33P labelling. 相似文献
73.
Chromosomal localization and linkage mapping of a powdery mildewresistance gene were conducted in the resistant wheat line Pova, derivedfrom a Triticum aestivum cv. Poros-Aegilops ovata-alien additionline. Monosomic analysis revealed that a major dominant gene was locatedon chromosome 7D. This gene possessed a distinct disease response patternagainst a differential set of Blumeria graminis tritici isolates andsegregated independently from resistance gene Pm19 also located onwheat chromosome 7D. Molecular genetic analysis showed that theresistance gene in Pova was specifically located on the long arm ofchromosome 7D closely linked to one RFLP and three AFLP markers. It isproposed that the new gene be designated Pm29. 相似文献
74.
Petrov DA Sangster TA Johnston JS Hartl DL Shaw KL 《Science (New York, N.Y.)》2000,287(5455):1060-1062
Eukaryotic genome sizes range over five orders of magnitude. This variation cannot be explained by differences in organismic complexity (the C value paradox). To test the hypothesis that some variation in genome size can be attributed to differences in the patterns of insertion and deletion (indel) mutations among organisms, this study examines the indel spectrum in Laupala crickets, which have a genome size 11 times larger than that of Drosophila. Consistent with the hypothesis, DNA loss is more than 40 times slower in Laupala than in Drosophila. 相似文献
75.
Heini Kujala Miguel B. Araújo Wilfried Thuiller Mar Cabeza 《Biological conservation》2011,(10):2450-2458
Gap analysis is a widely used method for assessing the representation of species in protected area (PA) networks. However, representation does not imply persistence. Here, we investigated whether gap analysis may result in misleading conservation guidelines by comparing the representation to two indicators of persistence. We ran a gap analysis with Finnish breeding birds and identified conservation priorities based on current distribution patterns. We tested the sensitivity of these results by using two target setting schemes and several thresholds defining the amount of protected area, and found the levels of representation identified by gap analysis to be robust. We then compared the gap analysis results with recent population trends and projected changes in potential suitable climate under different climate change scenarios for the year 2050. We show that although high latitude species are well represented in PAs, they are currently declining and are projected to lose climatic suitability in the near future. In contrast, low latitude species with poor representation in PAs have increasing population trends and are generally expected to expand their ranges into protected areas in the near future. This study demonstrates with empirical data a mismatch between representation in PAs and population trends, resulting in misleading understanding of current PA effectiveness. The mismatch is linked to the latitude of species distributions and corresponds to expected future changes, indicating that the patterns are potentially driven by climate change. We therefore urge practitioners and researchers to include better indicators of persistence in gap-analysis frameworks even for short term assessments. 相似文献
76.
77.
Volkman SK Hartl DL Wirth DF Nielsen KM Choi M Batalov S Zhou Y Plouffe D Le Roch KG Abagyan R Winzeler EA 《Science (New York, N.Y.)》2002,298(5591):216-218
The detection of single-nucleotide polymorphisms in pathogenic microorganisms has normally been carried out by trial and error. Here we show that DNA hybridization with high-density oligonucleotide arrays provides rapid and convenient detection of single-nucleotide polymorphisms in Plasmodium falciparum, despite its exceptionally high adenine-thymine (AT) content (82%). A disproportionate number of polymorphisms are found in genes encoding proteins associated with the cell membrane. These genes are targets for only 22% of the oligonucleotide probes but account for 69% of the polymorphisms. Genetic variation is also enriched in subtelomeric regions, which account for 22% of the chromosome but 76% of the polymorphisms. 相似文献
78.
79.
Using high-resolution transmission electron microscopy, we obtained structure images of strontium titanate (SrTiO3) with a clearly resolved oxygen sublattice along different crystallographic directions in the bulklattice and for a Sigma3 tilt grain boundary. Comparison with image simulations showed that the grain boundary contains oxygen vacancies. Measurements of atom displacements near the grain boundary revealed close correspondence with theoretical calculations. 相似文献
80.
The mechanisms that protect mammalian cells against amino acid deprivation are only partially understood. We found that during an acute decrease in external amino acid supply, before up-regulation of the autophagosomal-lysosomal pathway, efficient translation was ensured by proteasomal protein degradation. Amino acids for the synthesis of new proteins were supplied by the degradation of preexisting proteins, whereas nascent and newly formed polypeptides remained largely protected from proteolysis. Proteasome inhibition during nutrient deprivation caused rapid amino acid depletion and marked impairment of translation. Thus, the proteasome plays a crucial role in cell survival after acute disruption of amino acid supply. 相似文献