Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
hanh doi » thanh doi, hanh noi, hang doi
va trien » va truyen, va thiet, va tuyen
vu sach » vu bach, su sach, vu khach
hieu ve » hieu va, hieu van
va hanh » van hanh, va thanh, va danh
nang o » nang co, nang ho, nang ro
ve cac » va cac, vien cac
doi va » hoi va, noi va, dai va
o hoi » co hoi, o hoc, o hai

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((vu sach) or (hoc sach)) ky nang o hoi. hieu ve cac nuoc va hanh doi va trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((vu sach) OR (hoc sach)) ky nang o hoi. hieu ve cac nuoc va hanh doi va trien.
• Adding a wildcard symbol may retrieve word variants: ((vu sach) or (hoc sach)) ky nang o hoi. hieu ve cac nuoc va hanh doi va trien*.