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951.
952.
W. G. D. Fernando A. K. Watson T. C. Paulitz 《European journal of plant pathology / European Foundation for Plant Pathology》1996,102(1):1-7
Colletotrichum coccodes is currently being investigated as a mycoherbicide against the weed velvetleaf (Abutilon theophrasti). Two isolates ofPseudomonas spp. (Ps2 and Ps5) reduced the percentage of germ tubes and increased appressorial formation ofC. coccodes on detached leaves of velvetleaf. A study was conducted to see whether this effect could be attributed to competition for nutrients or iron betweenC. coccodes andPseudomonas spp. Ps2 and Ps5 had no effect on early spore germination, but reduced the percentage of germ tubes at 24 and 30 h, compared to the nontreated control. This reduction was diminished by the addition of nutrients but not Fe3+. Ps2 and Ps5 stimulated the formation of dark-coloured appressoria without germ tubes (AWGT), but this stimulation was diminished by the addition of nutrients or Fe3+. Germ tube branching at 30 h was also inhibited by the bacteria, but was not diminished by the addition of nutrients or iron. EDTA stimulated conidial germination at 10 h, which was reduced by the addition of Fe3+. However, EDTA did not stimulate the formation of appressoria (AWGT). These results suggest that the reduction in the percentage of germ tubes and the increase in the percentage of appressoria induced by the bacteria may be due to the competition for carbon or nitrogen. Iron competition may also be involved in the stimulation of appressorial formation, but not in the reduction in germ tube percentage and branching. Phylloplane bacteria may compete for carbon, nitrogen and iron, limiting the saprophytic phase of the pathogen on the phylloplane and accelerating the development of the parasitic phase. This may enhance the field efficacy ofC. coccodes as a biocontrol agent against velvetleaf. 相似文献
953.
农艺措施对大豆籽粒蛋白质和脂肪含量的影响 总被引:11,自引:0,他引:11
探讨了栽培密度、撒可富专用肥、思德富多元长效肥等农艺措施对大豆籽粒蛋白质和脂肪含量的影响。结果表明 ,密度对蛋白质含量、脂肪含量和蛋白脂肪总含量的影响不大。在各种栽培密度中 ,品种九三 97- 6 0是在 30万株 /hm2 时籽粒的蛋白质含量、脂肪含量和蛋白脂肪总含量均达到最高值 ,而对于品种九三 96 - 12 7来说 ,是在 2 5万株 /hm2 时三者达到最高。并且 ,蛋白质含量、脂肪含量及蛋白脂肪总含量对栽培密度敏感程度因品种而异。撒可富专用肥和思德富多元长效肥均使蛋白质含量增加 ,使脂肪含量降低。施用撒可富专用肥后 ,蛋白脂肪总含量变化因处理而异。施用思德富后 ,蛋白脂肪总含量有所增加。 相似文献
954.
955.
956.
速效肥和缓释肥对草坪蒸散量的影响 总被引:1,自引:0,他引:1
2002年5~11月在田间条件下就速效肥和缓释肥对草坪蒸散量的影响进行了研究.结果表明 施肥后草坪的蒸散量增大,其中,速效肥处理超过对照96.1mm,多耗水17.1%;速效肥+缓释肥和缓释肥处理分别增加了60.7mm和52.0mm,多耗水10.8%和9.2%;速效肥处理草坪蒸散量明显高于速效肥+缓释肥和缓释肥处理(P<0.05).施肥提高蒸散量的原因是增大了草坪草的生长速度及分蘖密度.缓释肥处理生长速度的增加幅度较小,株丛密度较高,且各月份比较稳定,速效肥处理则波动很大;此外,施用缓释肥更有利于地下生物量的积累.综合比较,在草坪管理中应减少速效肥的使用量,适当增加缓释肥的应用比例. 相似文献
957.
958.
氮肥对保水剂吸水保肥性能的影响 总被引:7,自引:0,他引:7
测定保水剂在不同氮肥(尿素、碳酸氢铵、硝酸铵、硫酸铵、氯化铵)溶液中的吸水倍率和对肥料养分的吸持量,分析不同氮肥对保水剂吸水、保肥性能的影响。结果表明:保水剂在各种氮肥溶液中吸水倍率显著下降,并随肥料浓度的增加下降幅度增加;受影响程度聚丙烯酸钠盐型保水剂大于聚丙烯酰胺-丙烯酸盐型保水剂;不同氮肥对保水剂吸水倍率的影响按尿素、碳酸氢铵、硝酸铵、硫酸铵、氯化铵顺序递增。保水剂在大量吸水的同时,也对溶液中的肥料分子或者离子有吸持作用,吸持量均随肥料浓度的增加而增加;保水剂和肥料品种不同,吸持量也不同;除尿素外,保水剂对肥料的吸持率随肥料浓度的增加而降低,最高浓度下,吸持率按硝酸铵、碳酸氢铵、氯化铵、硫酸铵、尿素次序依次增大。 相似文献
959.
Field tests of a prototype microwave‐based weed killer machine were conducted on Abutilon theophrasti, Panicum miliaceum, lucerne and oilseed rape pure stands. The approach can be considered a thermal weed control method, the microwave radiation causing dielectric heating of plant tissue water that eventually kills the plant. The method could overcome the limitations of other thermal methods, such as fire risk with flaming or the heavy loads required for hot water treatments. Species were effectively controlled by microwave irradiation, but their sensitivity and the evolution of damage symptoms over time differed. Lucerne showed no sigmoidal response and was the least affected by the treatment, while a log‐logistic curve expressed the dose–response relationships of the other species quite well. The estimated microwave dose for a 90% dry weight reduction ranged from 1015 kJ m?2 in A. theophrasti to 3433 kJ m?2 in P. miliaceum. Energy cost evaluation indicated that increased efficiency is required for this technique to compete with other thermal methods. Microwave efficiency could be increased by a flux configuration that minimizes soil penetration and maximizes absorption by plants, which, in turn, depends on plant growth form. 相似文献
960.
In 2004 the banded greenhouse thrips,Hercinothrips femoralis (Reuter) (Thysanoptera: Thripidae), was recorded for the first time in greenhouse-grown organic banana in the area of Sitia
(northeastern Crete). Banana fruits were severely damaged by the thrips infestation and a typical smoky-red discoloration
of the fruit was observed. Pest control was poor using either high-pressure washing with potassium fatty acids, or commercially
available thrips predatorsNeoseiulus cucumeris (Oudemans) (Acari: Phytoseiidae) andOrius laevigatus (Fieber) (Hemiptera: Anthocoridae). During 2005H. femoralis was also found causing severe damage in conventional banana plantations in Arvi, the main banana-growing area of Crete.
http://www.phytoparasitica.org posting Sept. 17, 2006. 相似文献