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为了解卷烟抽吸过程中重金属元素的分布规律、转移率和转移量,采用微波消解前处理烟叶样品及电感耦合等离子体质谱法 (ICP-MS)检测了 4个处理有代表性的烤烟 C3F等级烟叶样品燃吸后 Pb,Cr,Cu,As,Cd,Hg等 6种重金属元素在灰分、滤嘴、其他 (烟蒂和侧流烟气)、主流烟气气相及粒相中的转移率及残留量。结果表明:汞在主流烟气气相中能被检测出,其余5种重金属元素未被检测到;6种重金属元素在烟支燃吸过程中大部分均转移至灰分、其他 (烟蒂和侧流烟气)中,只有少量转移至主流烟气粒相 (转移率低于 3.5%)和滤嘴 (转移率低于 8.5%)中;就主流烟气粒相中残留量趋势为:高浓度处理〉中等浓度处理〉低浓度处理〉空白对照。 相似文献
874.
The effectiveness of the polyethylene stretch‐film barrier to air infiltration is the major factor affecting the preservation of silage in bales. Three separate experiments investigated the effects of the number of layers of stretch‐film cover, film colour, stretch extent, film type and frequency of bale handling on gas composition, surface mould growth and conservation characteristics of baled grass silages. Monitoring gas composition in bales during ensiling proved useful for assessing the success with which wrapped bales were stored anaerobically. Under good storage conditions the early stages of ensiling were characterized by the rapid reduction of O2 concentration in the bale and the creation of a CO2‐rich environment. However, wrapping bales in only two layers of stretch‐film failed to create the anaerobic conditions required for a successful fermentation and the inhibition of visible fungal growth. In contrast, a minimum of four layers of stretch‐film were required to achieve suitably anaerobic conditions, but the additional benefits of applying more layers were relatively small. Under temperate climatic conditions with moderate solar radiation, film colour had little effect on the gas composition in baled silage. Likewise, the extent of stretching applied to the film at wrapping and film type had no influence on gas composition, baled silage quality or mould development. However, frequent mechanical handling of bales after wrapping had a negative effect on gas composition and surface mould growth, and thus should be kept to a minimum. 相似文献
875.
Setiyo Gunawan Syahrizal MaulanaKhairiel Anwar Tri Widjaja 《Industrial Crops and Products》2011,33(3):624-628
Biodiesel is a biodegradable, renewable, non-toxic and environmentally friendly alternative fuel. The cost of raw materials comprises 60-88% of the production cost in commercial biodiesel (fatty acid methyl esters, FAMEs) production. Therefore, the use of low-cost raw material as a substrate and an in situ process for biodiesel production are being preferred. In this case, rice bran, which contains 13.5% oil, was an interesting substrate. In situ esterification of high-acidity rice bran with methanol and sulfuric acid catalyst was investigated. The individual and interaction effects of methanol to rice bran ratio, sulfuric acid catalyst concentration and reaction time on purity and recovery of biodiesel were discussed. Our results suggest that under the following operation conditions: methanol to rice bran ratio of 5 mL/g, sulfuric acid concentration in methanol of 1.5 vol.%, and reaction time of 60 min, an in situ esterification operated on rice bran could yield FAMEs with a high purity and recovery. By applying an in situ esterification with n-hexane/water extractions, Indonesia will be succesfull in obtaining biodiesel from rice bran up to 96,000 ton per year. 相似文献
876.
877.
施用生物炭对农田土壤氮素转化关键过程的影响 总被引:4,自引:0,他引:4
生物炭作为一种土壤改良剂,施入土壤后不仅能有效改善土壤结构,提高土壤对营养元素的吸附能力,还可减少温室气体的排放,增强生物固氮能力,因此在农业生产和缓解气候变化方面有着巨大的应用前景。生物炭的输入将直接影响农田土壤氮素的循环和转化,本文结合国内外大量文献,综合分析总结了施用生物炭对土壤氮素转化过程的影响,重点从生物炭对土壤氮素矿化、氮素损失以及硝化、反硝化作用和生物固氮过程的影响过程展开阐述。并在此基础上,提出今后应加强生物炭对氮素转化的作用机理及对环境的长期正负效应研究,特别是对相关微生物群落的多样性、丰度以及土壤酶活性方面的研究,同时提出相关研究应建立在统一的生物炭标准之上,以明确区分生物炭的作用效果及其作用机制。 相似文献
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879.
The second-order analysis approach for the cycle of Stirling engine is amended on the basis of mechanical loss and the temperature check of heater and radiator. Stirling engine is taken as the object, the alternating flow and heat exchange process of GPU-3 Stirling engine is simulated, and the changing rules of its internal pressure, temperature, velocity, power and efficiency are obtained. The simulation results are identical to the test results of NASA. The amended second-order analysis approach is used to analyze the effect of engine’s rotating speed, working substance and average pressure on the engine’s output performance. The error of the amended approach is less than 20%. The approach may be useful for the optimization design and the characteristic analysis of Stirling engine. 相似文献
880.
花椒精油的提取、抗菌活性研究及GC-MS分析 总被引:1,自引:1,他引:0
中国是花椒主产地。花椒的品种、生长环境以及提取方法的不同都会导致花椒精油化学组成与含量的差异。对产自山东德州的花椒采用索氏提取法提取花椒精油,分析精油抗菌活性,采用气相-质谱联用仪(GC-MS)分析精油化学成分。结果表明,不同溶剂提取所得精油在颜色、气味、状态等方面差别明显,对微生物抑制程度也不同,其中,乙醚提取的精油抗菌活性最强,对7种受试菌均有明显抑制作用。GC-MS显示在匹配度大于80%时,乙醚和石油醚提取的精油分别鉴定出45和63种物质,酮类为主要组分,2种精油中都含有大量的未被报道过的1(- 2-羟基-4,6-甲氧基苯基)乙酮。花椒精油作为花椒的重要功能成分,将会在食品呈香及抑菌防腐方面发挥重要的作用。 相似文献