Perhaps you should try some spelling variations:
bach thuc » cach thuc, bach thu, thach thuc
hieu viec » nhieu viec, hieu ve, sieu viet
viec bach » vien bach, viec ban, viec bao
nang mai » nang ma, nang tai, lang mai
mai khoi » mai khoa, tai khoa, cac khoi
va hanh » van hanh, va thanh, va danh
tu sach » thu sach, su sach, te sach
sach tu » sach thu, cach tu, sach ty
tu nang » tru nang, tu nong, tu nano
thuc va » thuc vat, thuc dan, thuc day
vi hoa » voi hoa, bi hoa, vi ha
va hoa » van hoa, va hoc, ma hoa
vi hoc » li hoc, va hoc

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 tu nang mai khoi. hieu viec bach thuc va hanh ((((vi hoa) OR (va hoa))) or (vi hoc)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach tu nang mai khoi. hieu viec bach thuc va hanh ((((vi hoa) OR (va hoa))) OR (vi hoc)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach tu nang mai khoi. hieu viec bach thuc va hanh ((((vi hoa) OR (va hoa))) or (vi hoc)) viet".
• Adding a wildcard symbol may retrieve word variants: tu sach tu nang mai khoi. hieu viec bach thuc va hanh ((((vi hoa) OR (va hoa))) or (vi hoc)) viet*.