Perhaps you should try some spelling variations:
nang mai » nang ma, nang tai, lang mai
su sach » so sach, vu sach
thuc va » thuc vat, thuc dan, thuc day
hang vi » hang va, hanh vi, khang voi
hang di » hang doi, hang dien, hang dich
ca viet » va viet, co viet, hoa viet
truc va » thuc vat, trung va
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
y nang » ky nang, ly nang, v nang
va cam » va cham, va cac, va cao

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 nang mai hoi. hieu va cam ((truc va) or (thuc va)) ((hang di) OR (hang vi)) ca viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang mai hoi. hieu va cam ((truc va) OR (thuc va)) ((hang di) OR (hang vi)) ca viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang mai hoi. hieu va cam ((truc va) or (thuc va)) ((hang di) OR (hang vi)) ca viet".
• Adding a wildcard symbol may retrieve word variants: su sach y nang mai hoi. hieu va cam ((truc va) or (thuc va)) ((hang di) OR (hang vi)) ca viet*.