Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
lang van » dang van, tang van, hoang van
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
va danh » va dinh, va dan, va hanh
xa danh » dia danh, nam danh, van danh
va tham » van tham, va cham, va thanh
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
le cua » ly cua
cua te » cua tu

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

• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((nang ma) OR (lang van)) hoi. hieu va tham thuc ((xa danh) OR (va danh)) le cua te~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty ((nang ma) or (lang van)) hoi. hieu va tham thuc ((xa danh) OR (va danh)) le cua te~".
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((nang ma) or (lang van)) hoi. hieu va tham thuc ((xa danh) OR (va danh)) le cua te*.