Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
nang ma » tang ma, sang ma, nang cao
van bac » van ban, van bao, van hac
van hai » van ha, van chat, van hanh
thuc va » thuc vat, thuc dan, thuc day
va xanh » va danh, va hanh, va anh
xanh di » danh di, vanh dai, xanh tai
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, xa hoi, ma hoa
di cua » dai cua, doi cua, de cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach ky nang ma hoi. hieu ((van bac) or (van hai)) thuc va xanh di cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu ((van bac) OR (van hai)) thuc va xanh di cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu ((van bac) or (van hai)) thuc va xanh di cua tre*.