Perhaps you should try some spelling variations:
tang lap » sang lap, tan lap, tang ap
su sach » so sach, vu sach
ky tang » ky nang, ky dang, kho tang
lap lai » lap tai, lay lai, lam lai
doan vi » doan va, don vi, doan thi
sach ky » sac ky, sach y, sach ty
vi cua » vai cua, di cua
cua te » cua tu
luc va » tuc va, loc va
va cam » va cham, va cac, va cao
ve cam » ve cham, ve cac, ve cai

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky tang lap lai. hieu ((ve cam) OR (va cam)) ((luc va) or (duc va)) doan vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky tang lap lai. hieu ((ve cam) OR (va cam)) ((luc va) OR (duc va)) doan vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky tang lap lai. hieu ((ve cam) OR (va cam)) ((luc va) or (duc va)) doan vi cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky tang lap lai. hieu ((ve cam) OR (va cam)) ((luc va) or (duc va)) doan vi cua te*.