Perhaps you should try some spelling variations:
nay thuc » nam thuc, cay thuc, day thuc
hanh vai » hanh vi, hanh tai, hanh van
hanh va » hang va, hanh vi
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua
ca tren » cau tren, cu tren, la tren
va nay » va ngay, va cay

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y ((nang ma) or (nang x)) hoi. hieu va nay thuc va ((hanh vai) or (hanh va)) ca tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (nang x)) hoi. hieu va nay thuc va ((hanh vai) OR (hanh va)) ca tren.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) or (nang x)) hoi. hieu va nay thuc va ((hanh vai) or (hanh va)) ca tren*.