Perhaps you should try some spelling variations:
hieu viec » nhieu viec, hieu ve, sieu viet
tuan thai » xuan thai, tuan khai, tuan tai
cau tren » cu tren, dau tren, ca tren
van tuan » van quan, van ban, anh tuan
nuoc van » nuoc va, nuoc san, luoc van
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
viec cac » vien cac, viec cua, viec lam
cuu tre » cua tre, cau treo
nang o » nang co, nang ho, nang ro
tu san » thu san, tu ban, tu can
tu bac » tu ban, tu cac, tu bat
o lai » o lao

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((tu bac) or (tu san)) ky nang o lai. hieu viec cac nuoc van tuan thai ((cuu tre) or (cau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu bac) OR (tu san)) ky nang o lai. hieu viec cac nuoc van tuan thai ((cuu tre) OR (cau tren)).
• Adding a wildcard symbol may retrieve word variants: ((tu bac) or (tu san)) ky nang o lai. hieu viec cac nuoc van tuan thai ((cuu tre) or (cau tren))*.