Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
dau tren » dau tien, dat tren, dau tieng
mang xa » lang xa, mang may, dang xay
nang ma » tang ma, sang ma, nang cao
va cham » va chat, va tham
soc van » hoc van, oc van, sac van
vi dau » vi dai, va dau, bi dau

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y ((mang xa) or (nang ma)) hoi. lieu va cham soc van hanh vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((mang xa) OR (nang ma)) hoi. lieu va cham soc van hanh vi dau tren*.