Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
phuc may » hoc may, chua may, truc may
dau tren » dau tien, dat tren, dau tieng
luc may » truc may
vu nang » vuc nang, va nang, vu dang
tinh vi » trinh vi, tinh voi, tinh va
va tham » van tham, va cham, va thanh
v nang » va nang, van nang, voi nang
vi dau » vi dai, va dau, bi dau
o hoi » co hoi, o hoc, o hai

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 ((v nang) or (vu nang)) o hoi. lieu va tham ((luc may) OR (phuc may)) tinh vi dau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ((v nang) OR (vu nang)) o hoi. lieu va tham ((luc may) OR (phuc may)) tinh vi dau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ((v nang) or (vu nang)) o hoi. lieu va tham ((luc may) OR (phuc may)) tinh vi dau tren".
• Adding a wildcard symbol may retrieve word variants: thu sach ((v nang) or (vu nang)) o hoi. lieu va tham ((luc may) OR (phuc may)) tinh vi dau tren*.