Perhaps you should try some spelling variations:
thanh dieu » thanh lieu, than dieu, hanh dieu
thien van » thi van
dieu tra » dieu tri, kiem tra, dieu cua
so sach » so sanh, bo sach, co sach
truc va » thuc va, thuc vat, trung va
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
nang co » nang cao, nang doc, nang noi
tuc va » thuc va, tuc xa, duc va
co hoi » co hoc, co loi
tra te » tra tu

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: so sach ky nang co hoi. ((hieu va) or (thien van)) cam ((tuc va) OR (truc va)) thanh dieu tra te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang co hoi. ((hieu va) OR (thien van)) cam ((tuc va) OR (truc va)) thanh dieu tra te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang co hoi. ((hieu va) or (thien van)) cam ((tuc va) OR (truc va)) thanh dieu tra te".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang co hoi. ((hieu va) or (thien van)) cam ((tuc va) OR (truc va)) thanh dieu tra te*.