Perhaps you should try some spelling variations:
nang hoa » nang hoat, hang hoa, nang hoc
va triet » va thiet, va trien, ve triet
hieu va » lieu va, hieu qua
sach ky » sach y, sach ty, sach kem
va hanh » van hanh, va thanh, va danh
cao xuc » cam xuc, cao duc, cao suc
sac ky » cac ky, sai ky
va cao » va cac, va co, va dao
va dan » ca dan, va dao, va dau
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: thuat ((sach ky) OR (sac ky)) nang hoa hoc. hieu va cao xuc ((va hanh) or (va dan)) vi va triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat ((sach ky) OR (sac ky)) nang hoa hoc. hieu va cao xuc ((va hanh) OR (va dan)) vi va triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat ((sach ky) OR (sac ky)) nang hoa hoc. hieu va cao xuc ((va hanh) or (va dan)) vi va triet".
• Adding a wildcard symbol may retrieve word variants: thuat ((sach ky) OR (sac ky)) nang hoa hoc. hieu va cao xuc ((va hanh) or (va dan)) vi va triet*.