Perhaps you should try some spelling variations:
cau theo » cau thi, cau tao
nam thuc » nam thuoc, nam thu, nam tu
hanh hai » thanh hai, nhanh hai, hang hai
hai cau » hai chau, hai chu, hai hau
va hanh » van hanh, va thanh, va danh
su sach » so sach, vu sach
lv nang » ly nang
hieu va » lieu va, hieu qua
v nang » va nang, vu nang, van nang

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 ((v nang) or (lv nang)) cau hoi. hieu va ((nam thuc) OR (am thuc)) va hanh hai cau theo~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((v nang) OR (lv nang)) cau hoi. hieu va ((nam thuc) OR (am thuc)) va hanh hai cau theo.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((v nang) or (lv nang)) cau hoi. hieu va ((nam thuc) OR (am thuc)) va hanh hai cau theo".
• Adding a wildcard symbol may retrieve word variants: su sach ((v nang) or (lv nang)) cau hoi. hieu va ((nam thuc) OR (am thuc)) va hanh hai cau theo*.