Perhaps you should try some spelling variations:
nang hoa » nang hoat, hang hoa, nang hoc
nam thuc » nam thuoc, am thuc, nam thu
vat hanh » vat thanh, van hanh, va hanh
sach ky » sac ky, sach ty, sach kem
hoa hoi » khoa hoi, hoa hoc, hoa doi
hieu ve » hieu va, hieu van
ve nam » he nam, va nam, le nam
vi su » ve su, ki su, oi su

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 ky) or (sach y)) nang hoa hoi. hieu ve nam thuc vat hanh ((vi su) OR (va su)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ky) OR (sach y)) nang hoa hoi. hieu ve nam thuc vat hanh ((vi su) OR (va su)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ky) or (sach y)) nang hoa hoi. hieu ve nam thuc vat hanh ((vi su) OR (va su)) triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach ky) or (sach y)) nang hoa hoi. hieu ve nam thuc vat hanh ((vi su) OR (va su)) triet*.