Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
tu sach » su sach, te sach, tu cach
va hanh » van hanh, va thanh, va danh
vu kham » vu khanh
vu cham » va cham, tu cham, qua cham
nang ma » tang ma, sang ma, nang cao
ma hoi » mai hoi, xa hoi, ma hoa
luc va » duc va, tuc va, loc va
vi va » vi van, vai va, vu va
thiet » thieu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu sach) or (thu sach)) ky nang ma hoi. hieu ((vu cham) or (vu kham)) luc va hanh vi va thiet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang ma hoi. hieu ((vu cham) OR (vu kham)) luc va hanh vi va thiet.
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang ma hoi. hieu ((vu cham) or (vu kham)) luc va hanh vi va thiet*.