Perhaps you should try some spelling variations:
vanh dai » van dai, vanh tai, lanh dao
thuc cao » thuoc cao, thuc co, thuc can
thuc cay » thuc day, thuc can, thuc xay
nang mai » nang ma, nang tai, lang mai
va tham » van tham, va cham, va thanh
mai hoi » mai khoi, dai hoi, lai hoi
sach v » sach va, sach y, sach vay
sach 2 » sach y
cua su » qua su

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) OR (sach 2)) nang mai hoi. lieu va tham ((thuc cay) or (thuc cao)) vanh dai cua su~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sach v) OR (sach 2)) nang mai hoi. lieu va tham ((thuc cay) OR (thuc cao)) vanh dai cua su.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su ((sach v) OR (sach 2)) nang mai hoi. lieu va tham ((thuc cay) or (thuc cao)) vanh dai cua su".
• Adding a wildcard symbol may retrieve word variants: su ((sach v) OR (sach 2)) nang mai hoi. lieu va tham ((thuc cay) or (thuc cao)) vanh dai cua su*.