Perhaps you should try some spelling variations:
van hanh » van thanh, ban hanh, van anh
xanh doi » xanh di, thanh doi, tinh doi
tu sach » thu sach, su sach, te sach
doi cua » dai cua, hoi cua
va xanh » va danh, va hanh, va anh
truc va » thuc va, thuc vat, trung va
van hai » van ha, van chat, van phan
van bac » van ban, van bao, van hac
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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: tu sach y nang ma hoi. hieu ((van bac) or (((van hai) OR (van hanh)))) truc va xanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang ma hoi. hieu ((van bac) OR (((van hai) OR (van hanh)))) truc va xanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang ma hoi. hieu ((van bac) or (((van hai) OR (van hanh)))) truc va xanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang ma hoi. hieu ((van bac) or (((van hai) OR (van hanh)))) truc va xanh doi cua tre*.