Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
phan lap » phan dau
thuc dan » thuc hanh, hoc dan, thuc vat
truc va » thuc va, thuc vat, trung va
tu sach » thu sach, su sach, te sach
hieu vu » hieu va, hieu ve, hieu su
hoi hoi » hoi hoc, hoc hoi, hoi doi
ty nang » ky nang, ty hang, ly nang
vu cham » va cham, vu kham, tu cham
lap su » lap du, lap tu, lai 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 ((ty nang) OR (ty xang)) hoi hoi. hieu vu cham ((truc va) or (thuc dan)) phan lap su triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((ty nang) OR (ty xang)) hoi hoi. hieu vu cham ((truc va) OR (thuc dan)) phan lap su triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((ty nang) OR (ty xang)) hoi hoi. hieu vu cham ((truc va) or (thuc dan)) phan lap su triet".
• Adding a wildcard symbol may retrieve word variants: tu sach ((ty nang) OR (ty xang)) hoi hoi. hieu vu cham ((truc va) or (thuc dan)) phan lap su triet*.