Perhaps you should try some spelling variations:
sach tren » sach tien, sach tranh
tren quoc » tran quoc, trung quoc, trinh quoc
quoc khi » buoc khoi, quoc thai, cuoc khoi
tac pham » thuc pham, san pham
duc kham » duoc kham, duc pham, duc tham
su sach » so sach, vu sach
tu tac » tu trac, tu tai, tu cac

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (( su sach tren quoc khi đong luc ) or ( tu tac pham duc kham đong luc ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( su sach tren quoc khi đong luc ) OR ( tu tac pham duc kham đong luc )).
• Adding a wildcard symbol may retrieve word variants: (( su sach tren quoc khi đong luc ) or ( tu tac pham duc kham đong luc ))*.