Perhaps you should try some spelling variations:
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
lang vai » lang van, lang dai, lang mai
lang hai » lang chai, lang thai, lang ha
su sach » so sach, vu sach
nang xa » nang x, lang xa, nang ma
hieu va » hieu qua
sach 2 » sach y
2 nang » v nang
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach 2 nang xa hoi. ((hieu va) OR (lieu va)) cac nuoc va ((lang vai) or (lang hai)) cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach 2 nang xa hoi. ((hieu va) OR (lieu va)) cac nuoc va ((lang vai) OR (lang hai)) cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach 2 nang xa hoi. ((hieu va) OR (lieu va)) cac nuoc va ((lang vai) or (lang hai)) cua te".
• Adding a wildcard symbol may retrieve word variants: su sach 2 nang xa hoi. ((hieu va) OR (lieu va)) cac nuoc va ((lang vai) or (lang hai)) cua te*.