validity 第1页

A summary of soil microbial biomass nitrogen Effects of water and fertilizer spatial coupling on nitrogen and phosphorus validity and yield effect of winter wheat （Triticum aestivum L.） Study on validity of genes for leaf rust resistance of wheat in Shanxi Calculating and testing cultivated land protection externality using Contingent Valuation Method Improving validity and reliability of contingent valuation method through reducing biases and errors: theory, method and application