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排序方式: 共有112条查询结果,搜索用时 31 毫秒
61.
近红外光谱法非破坏性测定玉米子粒粗淀粉含量的研究 总被引:1,自引:0,他引:1
采用偏最小二乘回归法,对近红外光谱法测定玉米完整子粒粗淀粉含量的可行性进行研究。结果表明,定标集和检验集的预测值与化学测定值间均达极显著正相关,相关系数分别为0.9610和0.9820,并具有较小的定标标准差和预测标准差,分别为0.707和0.666。所建立的校正模型具有较高的预测精度。 相似文献
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为了探讨青贮饲料的近红外光谱(NIRS)分析模型在不同类型光谱仪器之间的转移,以傅里叶变换型近红外光谱仪Nicolet ANTARIS作为主仪器,光栅型近红外光谱仪FOSS 6500作为从仪器,采用斜率/截距和局部中心化2种方法进行了研究.结果表明,经斜率/截距和局部中心化法转移之后,所建立校正模型的决定系数R2和交互验证决定系数R2cv均大于0.85.采用斜率/截距法转移之后,ANTARIS仪器校正模型对FOSS 6500仪器验证集的预测标准差为20.27 g/kg,系统偏差为-3.75,采用局部中心化法转移之后的预测标准差为27.67 g/kg,系统偏差为-6.17.2种方法模型转移后的预测结果与FOSS 6500仪器模型的预测结果(预测标准差为20.60 g/kg,系统偏差为-1.04)非常接近,比转移前的预测结果(预测标准差为39.65 g/kg,系统偏差为-33.60)有较大程度改善,2种方法均获得较好的转移效果. 相似文献
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Yuri Zharikov Robert W. Elner Philippa C. F. Shepherd David B. Lank 《Landscape Ecology》2009,24(1):129-144
Coastal landscapes with extensive intertidal mudflats provide non-breeding habitat for Arctic shorebirds. Few attempts have
been made to develop and test landscape-level models predicting the intertidal distribution of these birds. We modelled the
distribution of a Holarctic species, Dunlin (Calidris alpina), at a hemispherically important non-breeding site, the Fraser River Delta, British Columbia, Canada, in seasons with different
predator landscapes. We trained the models during a season when nocturnal predators were common and tested temporal transferability
of the models on independent datasets when nocturnal predators were absent. Snowy Owls (Nyctea scandiaca) influenced Dunlin distribution and thus model transferability. After accounting for their presence, models displayed good
to excellent discrimination, i.e. prediction of the instantaneous and cumulative (over low tide period) probability of mudflat
use by Dunlin, in fore- and backcasting applications. Model calibration was good or else, where over-prediction was observed,
the reason for the bias was identified. The distribution models may predict mudflat use by Dunlin and possibly related species
given relevant data describing the intertidal landscape. The models are amenable to GIS application, describe the amount of
use per hectare of the intertidal zone and can be used to determine and visualise relative and absolute suitability of intertidal
areas.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(9-10):1371-1383
Abstract The objective of this work was to calibrate, classify, and establish soil and plant reference norms for evaluating the nutritional status of the Horn plantain crop (Musa AAB, subgroup plantain cv. Horn). The sampling unit consisted of the “mother” plant and its corresponding soil at the fertilization band. Soil samples at depths of 0–20 cm and 21–40 cm were analyzed. A total of 221 sampling units were studied, hence, 442 soil and 221 leaf samples were used to develop the reference norms. A regression model with linear combinations of the soil and leaf variables for yield estimation was established by using the stepwise method. The model showed a high significant adjustment of 52% (R2) with normality of the standard residues. Four yield subclasses in kg cluster?1 as 10.9–13.9 (60 units), 14.0–17.9 (92 units), 18.0–19.9 (47 units), and 20 or more (17 units) were defined. With the means of the soil and leaf data linearly related with yield, the reference norms for each subclass were developed. The method thereby established permits to develop reference norms that can be used for the simultaneous interpretation of soil and leaf analysis data and for yield estimation of the Horn plantain crop. 相似文献
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《Communications in Soil Science and Plant Analysis》2012,43(8):685-698
Abstract Zinc availability was studied using five soils from Hawaii which had histories of massive phosphorus applications. Heavy phosphate fertilization usually increased extractable Zn, irrespective of the extractant used. The extra extractable Zn associated with the added P probably came from Zn as an accessory element in the fertilizer. Treble superphosphate commonly used in Hawaii contains about 1400 ppm Zn. The Zn content of phosphate fertilizers must be considered before making statements about the effect of fertilizer P on Zn solubility and availability in soils. Two solutions (0.1N HCl and 0.005M DTPA) were compared as Zn extractants for Hawaii soils. DTPA extracted less Zn than 0.1N HCl. Zinc extracted by repeated HCl treatment was more closely related to the labile Zn pool (E‐values and L‐values) than was DTPA‐extractable Zn. The results suggest that 0.1N HCl extractable Zn, Zn E‐value and Zn L‐value measured the quantity of a single fraction of soil Zn. Repeated extraction of soil with 0.1N HCl seems to be a suitable procedure for evaluating the Zn status of acid, highly weathered soils of Hawaii. 相似文献