Perhaps you should try some spelling variations:
hoc viet » hoc hien
nang xa » nang x, lang xa, nang ma
hieu va » lieu va, hieu qua
nay duc » ngay doc
va tinh » may tinh
tinh vi » trinh vi, tinh voi, tinh va
sac ky » cac ky, sai ky
va nay » va ngay, va cay
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: su ((sac ky) or (sach y)) nang xa hoi. hieu va nay duc va tinh vi hoc viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su ((sac ky) OR (sach y)) nang xa hoi. hieu va nay duc va tinh vi hoc viet.
• Adding a wildcard symbol may retrieve word variants: su ((sac ky) or (sach y)) nang xa hoi. hieu va nay duc va tinh vi hoc viet*.