Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cam thuc » am thuc, nam thuc, cam thu
va trien » va truyen, va thiet, va tuyen
sach dao » lanh dao
hanh tai » thanh tai, hang tai, han tai
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
van cam » van nam, van lam, van cau
sach lo » sach doi, sach hoi, sach moi
lang ha » long ha
ha hoi » hoa hoi, ha noi, xa hoi
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: te ((sach lo) OR (sach dao)) lang ha hoi. hieu van cam thuc va hanh tai ((va trien) or (cua te))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te ((sach lo) OR (sach dao)) lang ha hoi. hieu van cam thuc va hanh tai ((va trien) OR (cua te)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te ((sach lo) OR (sach dao)) lang ha hoi. hieu van cam thuc va hanh tai ((va trien) or (cua te))".
• Adding a wildcard symbol may retrieve word variants: te ((sach lo) OR (sach dao)) lang ha hoi. hieu van cam thuc va hanh tai ((va trien) or (cua te))*.