Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
lam duoc » nam duoc, luat duoc, lam thuoc
hieu van » thien van, lieu va, hieu ve
danh di » danh du, xanh di, danh dien
ma danh » va danh, ma dan, mo danh
duoc ma » duoc lam
hieu va » lieu va, hieu qua
di cua » dai cua, doi cua, de cua
nang o » nang co, nang ho, nang ro
cua te » cua tu
o hai » co hai, so hai, o lai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thuoc sach) or (thu hoach)) ky nang o hai. ((hieu van) OR (hieu va)) lam duoc ma danh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thuoc sach) OR (thu hoach)) ky nang o hai. ((hieu van) OR (hieu va)) lam duoc ma danh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thuoc sach) or (thu hoach)) ky nang o hai. ((hieu van) OR (hieu va)) lam duoc ma danh di cua te".
• Adding a wildcard symbol may retrieve word variants: ((thuoc sach) or (thu hoach)) ky nang o hai. ((hieu van) OR (hieu va)) lam duoc ma danh di cua te*.