Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hanh hanh » hanh han, xanh hanh, nhanh thanh
hieu van » hieu va, thien van, lieu va
va trien » va truyen, va thiet, va tuyen
lang xa » lang ha, dang xay, lang van
sach ty » sach y, sach tu, sach thu
cao duc » dao duc, giao duc, tao duoc
cao suc » cao su
nang xa » nang x, nang ma, mang xa
vi va » vi van, vai va, vu va

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 ty ((nang xa) or (lang xa)) hoi. hieu van ((cao duc) OR (cao suc)) hanh hanh vi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuoc sach ty ((nang xa) OR (lang xa)) hoi. hieu van ((cao duc) OR (cao suc)) hanh hanh vi va trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuoc sach ty ((nang xa) or (lang xa)) hoi. hieu van ((cao duc) OR (cao suc)) hanh hanh vi va trien".
• Adding a wildcard symbol may retrieve word variants: thuoc sach ty ((nang xa) or (lang xa)) hoi. hieu van ((cao duc) OR (cao suc)) hanh hanh vi va trien*.