有证标准物质

certified reference material

• dinnertime
• dinosaur
• direct
• direction
• directive
• directly
• director
• directory
• dirt
• dirty
• dirty water
• dis-
• disability
• disable
• disabled
• disadvantage
• disadvantaged
• disagree
• disagreement
• disagree on
• disagree with
• disappear
• disappearance
• disappoint
• disappointed