Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
vien cac » vien bach, vien dai, vien da
hanh vai » hanh vi, hanh va, hanh tai
vai cua » dai cua, hai cua, lai cua
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cuu tre, cua triet
nang xa » lang xa, nang ma, mang xa
ve cac » va cac

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 y ((nang xa) or (nang x)) hoi. hieu ((ve cac) OR (vien cac)) nuoc va hanh vai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach y ((nang xa) OR (nang x)) hoi. hieu ((ve cac) OR (vien cac)) nuoc va hanh vai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach y ((nang xa) or (nang x)) hoi. hieu ((ve cac) OR (vien cac)) nuoc va hanh vai cua tre".
• Adding a wildcard symbol may retrieve word variants: thuat sach y ((nang xa) or (nang x)) hoi. hieu ((ve cac) OR (vien cac)) nuoc va hanh vai cua tre*.