Perhaps you should try some spelling variations:
"trinh quan luan van hieu soat" » "tinh quang luan van hieu soat", "trinh luat luan van hieu soat", "trinh han luan van hieu soat", "trinh quan luan van hieu suat", "trinh quan luan van hieu hoat", "trinh quan luan van hieu luat", "trinh quan luan cao hieu soat", "trinh quan lan van hieu soat"
"minh quang tran van kiem soat" » "tinh quang tran van kiem soat", "dinh quang tran van kiem soat", "minh hoang tran van kiem soat", "minh quang tuan van kiem soat", "minh quang trung van kiem soat", "minh quang thanh van kiem soat", "minh quang tran van kiem toan", "minh quang tran va kiem soat", "minh quang tran van kien soat", "minh quang tran van hien soat"

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• Performing a fuzzy search may retrieve terms with similar spellings: (("trinh quan luan van hieu soat") or ("minh quang tran van kiem soat"))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("trinh quan luan van hieu soat") OR ("minh quang tran van kiem soat")).
• Removing quotes may allow a broader search: (( trinh quan luan van hieu soat ) or ( minh quang tran van kiem soat )).
• Adding a wildcard symbol may retrieve word variants: (("trinh quan luan van hieu soat") or ("minh quang tran van kiem soat"))*.