Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
hanh tai » thanh tai, hang tai, han tai
hanh dai » hanh dao, vanh dai, thanh dat
cac cac » cac cach, ca cac, cac bac
cac ban » cac dan, cac van, can ban
cua tre » cua te, cuu tre, cua triet
hieu ve » hieu va, hieu van
sang ma » tang ma, nang ma, sang tao
ky sang » ky nang, ky dang, ky tang
ma hoi » mai hoi, xa hoi, ma hoa
ve cac » va cac, vien cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) OR (thuat sach)) ky sang ma hoi. hieu ve cac cac ban ((hanh dai) or (hanh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ky sang ma hoi. hieu ve cac cac ban ((hanh dai) OR (hanh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (thuat sach)) ky sang ma hoi. hieu ve cac cac ban ((hanh dai) or (hanh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (thuat sach)) ky sang ma hoi. hieu ve cac cac ban ((hanh dai) or (hanh tai)) cua tre*.