Perhaps you should try some spelling variations:
dua tren » dung tren
hanh cac » hang cac, hanh cat, nhanh cay
sach ky » sac ky, sach y, sach ty
cuu tre » cua tre, cau tren, cau treo
thuc va » thuc vat, thuc dan, thuc day
tu sach » thu sach, su sach, te sach
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
tuc va » truc va, tuc xa, duc va
ma hoi » mai hoi, xa hoi, ma hoa

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 ky nang ma hoi. hieu va cac ((tuc va) OR (thuc va)) hanh cac ((cuu tre) or (dua tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky nang ma hoi. hieu va cac ((tuc va) OR (thuc va)) hanh cac ((cuu tre) OR (dua tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky nang ma hoi. hieu va cac ((tuc va) OR (thuc va)) hanh cac ((cuu tre) or (dua tren))".
• Adding a wildcard symbol may retrieve word variants: tu sach ky nang ma hoi. hieu va cac ((tuc va) OR (thuc va)) hanh cac ((cuu tre) or (dua tren))*.