Perhaps you should try some spelling variations:
thanh van » thanh san, thanh toan, thanh phan
thanh vai » thanh hai, thanh tai, thanh oai
nang tai » hang tai, tang tai, sang tai
tai khoa » da khoa, noi khoa
tu sach » thu sach, su sach, te sach
dua ban » dia ban, cua ban, qua ban
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, va cam

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 tai khoa. hieu ((ve cam) or (va cac)) dua ban ((thanh vai) OR (thanh van)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y nang tai khoa. hieu ((ve cam) OR (va cac)) dua ban ((thanh vai) OR (thanh van)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y nang tai khoa. hieu ((ve cam) or (va cac)) dua ban ((thanh vai) OR (thanh van)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y nang tai khoa. hieu ((ve cam) or (va cac)) dua ban ((thanh vai) OR (thanh van)) cua tre*.