Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
sach nay » sach hay, sach vay, sach nang
nay dang » nam dang, nao dang, nap dang
dang xay » dang van, van xay
manh hoi » manh hai, manh ho, manh hon
hoi cua » hoi chuc
va manh » van manh, va danh, va hanh
cua tre » cua te, cuu tre, cua triet
xay hoi » xa hoi, tay hoi, cay phoi
de tai » de thi, te tai
va cam » va cham, va cac, va cao
ve tai » te tai, le tai, ve tac

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach nay dang xay hoi. hieu ((((ve tai) OR (de tai))) or (va cam)) duc va manh hoi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach nay dang xay hoi. hieu ((((ve tai) OR (de tai))) OR (va cam)) duc va manh hoi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach nay dang xay hoi. hieu ((((ve tai) OR (de tai))) or (va cam)) duc va manh hoi cua tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach nay dang xay hoi. hieu ((((ve tai) OR (de tai))) or (va cam)) duc va manh hoi cua tre*.