Perhaps you should try some spelling variations:
cua viet » ca viet, hoa viet, cua vat
cam tuc » cam xuc, cam tu, nam thuc
su sach » so sach, vu sach
hieu va » lieu va, hieu qua
ma hoi » mai hoi, xa hoi, ma hoa
y tang » ky tang, 6 tang, 5 tang
va cam » va cham, va cac, va cao
7 tang » 6 tang
da cua » dai cua, day cua, dan cua

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 ((y tang) or (7 tang)) ma hoi. hieu va cam tuc ((va tinh) OR (may tinh)) da cua viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((y tang) OR (7 tang)) ma hoi. hieu va cam tuc ((va tinh) OR (may tinh)) da cua viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((y tang) or (7 tang)) ma hoi. hieu va cam tuc ((va tinh) OR (may tinh)) da cua viet".
• Adding a wildcard symbol may retrieve word variants: su sach ((y tang) or (7 tang)) ma hoi. hieu va cam tuc ((va tinh) OR (may tinh)) da cua viet*.