Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
danh dai » danh dau, danh di, danh sai
hoc sach » hoc sinh, hoc cac, hoc anh
thuc va » thuc vat, thuc dan, thuc day
truc va » thuc vat, trung va
ca chat » cao chat, cac chat, va chat
hieu ca » hieu cac, hieu cua, hieu va
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa

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 (hoc sach)) ky nang ma hoi. hieu ca chat ((truc va) OR (thuc va)) danh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (hoc sach)) ky nang ma hoi. hieu ca chat ((truc va) OR (thuc va)) danh dai cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (hoc sach)) ky nang ma hoi. hieu ca chat ((truc va) OR (thuc va)) danh dai cua tre*".