Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
danh vai » danh sai, danh va, doanh van
thuc dan » thuc hanh, hoc dan, thuc vat
sach ky » sac ky, sach ty, sach kem
thuc va » thuc vat, thuc day
hieu va » lieu va, hieu qua
vai su » va su, van su, lai su
x hoi » xa hoi, o hoi, x ho
va am » va lam, va cam

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

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