Perhaps you should try some spelling variations:
hanh dao » lanh dao, thanh dat, thanh dam
thuc dan » thuc hanh, hoc dan, thuc vat
tang van » dang van, hoang van, trong van
tu sach » thu sach, su sach, tu cach
dao cua » dai cua, day cua, dan cua
thuc va » thuc vat, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
van hoi » van hoa, van hoc, van hoe
ky tang » ky nang, ky dang, kho tang
te sach » toc sach
va cam » va cham, va cac, va cao

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) or (te sach)) ky tang van hoi. hieu va cam ((thuc va) OR (thuc dan)) hanh dao cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (te sach)) ky tang van hoi. hieu va cam ((thuc va) OR (thuc dan)) hanh dao cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (te sach)) ky tang van hoi. hieu va cam ((thuc va) OR (thuc dan)) hanh dao cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (te sach)) ky tang van hoi. hieu va cam ((thuc va) OR (thuc dan)) hanh dao cua tre*.