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排序方式: 共有5488条查询结果,搜索用时 31 毫秒
91.
92.
我国麦/稻秸秆板工业的发展与思考 总被引:8,自引:0,他引:8
通过回顾我国秸秆板工业化生产的发展历程及现状,分析了目前秸秆板生产设备与工艺存在的问题和差距,从多个方面就我国今后秸秆人造板发展有待改进的方向提出建议. 相似文献
93.
94.
Francis O. C. Nwonwu 《Agroforestry Systems》1987,5(4):455-462
The costs and benefits of the use of three labour alternatives: direct permanent, direct casual and taungya labour in Gmelina arborea pulpwood plantation establishment in Nigeria were investigated. Results show that cost per hectare is lowest with taungya labour and highest with permanent labour with savings in cost of as much as 30% and 47% by taungya labour over casual and permanent labour respectively. The net present value per hectare of investment is highest when taungya labour is used and lowest and negative with permanent labour. Also, the internal rate of return of investment is highest with taungya labour and lowest with permanent labour. The net present values and internal rates of return for Gmelina plantations calculated for the three pulp and paper mills in Nigeria show the same trend in favour of taungya labour. 相似文献
95.
96.
改性UF麦秸均质刨花板的工艺研究 总被引:1,自引:1,他引:1
通过试验确定了麦秸均质刨花板的主要工艺参数。其结果表明:10mm厚麦秸均质刨花板的较优工艺参数为热压温度150℃、热压时间8min、表层麦秸刨花的施胶量为10%、芯层麦秸刨花的施胶量为8%、板密度0.75g/cm3、表芯层刨花比例为3:7。按照以上工艺条件压制的麦秸均质刨花板性能已达到均质刨花板的要求。 相似文献
97.
98.
硫酸盐草浆黑液制粉状活性炭的研究 总被引:2,自引:0,他引:2
本文探讨硫酸盐草浆纸厂黑液的治理和利用,提出用酸化法从黑液中沉析木素制取粉状活性炭。大约生产10t草浆可制取1t优质粉状活性炭。同时还含有占总碱量24%的Na_2S可回收。排出的废液即使不再经过处理,其污染程度也已大大降低。 相似文献
99.
Satoshi Saito 《Journal of Forest Research》2002,7(3):137-143
The effects of a typhoon on forest dynamics and the response of major tree species were studied in a warm-temperate evergreen
broad-leaved forest in southwestern Japan. The strongest typhoon on record (T9313) passed through this region in 1993. Return
periods of typhoons over 30 ms−1 in instantaneous wind velocity and T9313 were estimated to be 2.2 and 104.5 years, respectively. Approximately 10% of all
stems suffered some damage from T9313 and annual stem mortality rose from 1.3 to 2.7%. The estimated period that the number
of stems would fall below 10% of the initial was four years shorter with T9313-class typhoons than without them. Thus, the
disturbance by T9313 was not catastrophic at the site although T9313 was an episodic typhoon. The short-term responses of
major tree species to T9313 were classified into four types: 1) blunt-response type with little decrease and recruitment of
stems in the DBH ≥ 5 cm class (Distylium racemosum), 2) retreat type with larger decrease than recruitment (e.g. Quercus acuta), 3) sharp-response type with a large decrease and much recruitment (e.g. Cinnamomum japonicum), and 4) advance type with less decrease than recruitment (Eurya japonica). Among the four regeneration types classified by previous studies (climax, light-demanding, subcanopy, and few-sapling),
the climax and few-sapling types each showed a specific short-term response, the blunt-response and retreat types, respectively,
that explains one aspect of the regeneration strategies of each type. On the other hand, the light-demanding or sub-canopy
type showed multiple short-term responses, indicating that each regeneration type contains species with various regeneration
strategies.
In this paper, I analyzed data from the database that was compiled by the Aya Research Team. 相似文献
100.
稻草原料表面特性FTIR和XPS分析 总被引:13,自引:0,他引:13
运用红外光谱(IR)和X射线光电子能谱分析(XPS)法,考察了热磨处理对稻草表面特性的影响。结果表明:稻草秸秆内表面的活性基团数量和氧碳元素百分比都明显高于外表面;经热磨处理,稻草纤维表面的羟基、甲基、亚甲基等官能团含量显著增加,氧碳元素百分比相对秸秆表面有大幅度提高,证明热磨处理能增强稻草表面活性,为脲醛树脂稻草中纤板制造的技术可行性提供了依据。 相似文献