Perhaps you should try some spelling variations:
thanh dam » thanh dat, thanh nam, thanh tam
nang lai » nang tai, mang lai, nang cai
hieu van » thien van, lieu va, hieu ve
hanh dao » lanh dao, thanh dat, doanh dao
so sach » so sanh, bo sach, co sach
cuu tre » cua tre, cau tren, cau treo
cam tuc » cam xuc, cam tu, nam thuc
sach ky » sac ky, sach y, sach ty
hieu va » lieu va, hieu qua
lai hoa » dai hoa, loai hoc

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 lai hoa. ((hieu van) or (hieu va)) cam tuc xa ((hanh dao) OR (thanh dam)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach ky nang lai hoa. ((hieu van) OR (hieu va)) cam tuc xa ((hanh dao) OR (thanh dam)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach ky nang lai hoa. ((hieu van) or (hieu va)) cam tuc xa ((hanh dao) OR (thanh dam)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: so sach ky nang lai hoa. ((hieu van) or (hieu va)) cam tuc xa ((hanh dao) OR (thanh dam)) cuu tre*.