ใจกล้า ส, กีรติจำเริญ ว. A STUDY OF LEARNING ACHIEVEMENT ON SAVE ENVIRONMENTS LEARNING UNIT AND PROBLEM SOLVING ABILITY OF GRADE 10 STUDENTS USING THE PROBLEM–BASED LEARNING. Res Comm Soc Dev J [internet]. 2019 Jan. 1 [cited 2026 Sep. 12];13(1):178-90. available from: https://so04.tci-thaijo.org/index.php/NRRU/article/view/185808