Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
mau thuc » mau thu, mau thuan, am thuc
hanh va » hang va, hanh vi
van mau » van dau, van cau, van hau
tu sach » thu sach, te sach, tu cach
nang ma » tang ma, sang ma, nang cao
su sach » so sach, vu sach
cua tre » cua te, cuu tre, cua triet
va cua » va chua, via cua, ca cua

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 (su sach)) ky ((nang ma) or (mang may)) hoi. hieu van mau thuc van hanh va cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (su sach)) ky ((nang ma) OR (mang may)) hoi. hieu van mau thuc van hanh va cua tre.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (su sach)) ky ((nang ma) or (mang may)) hoi. hieu van mau thuc van hanh va cua tre*.