Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
cac thuc » cach thuc, cac thu, can thuc
nhan tai » hang tai, van tai, toan tai
hanh tai » thanh tai, hang tai, han tai
hanh cat » hanh cac, hanh luat, nhanh cay
sach thi » sach thu, sach tai, sach thieu
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
hanh ca » hanh cac, hanh cua, hanh cad
hieu va » lieu va, hieu qua

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 thi ((hanh ca) OR (hanh cat)) hoi. hieu va cac thuc va ((hanh tai) or (nhan tai)) su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach thi ((hanh ca) OR (hanh cat)) hoi. hieu va cac thuc va ((hanh tai) OR (nhan tai)) su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach thi ((hanh ca) OR (hanh cat)) hoi. hieu va cac thuc va ((hanh tai) or (nhan tai)) su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach thi ((hanh ca) OR (hanh cat)) hoi. hieu va cac thuc va ((hanh tai) or (nhan tai)) su triet*.