Perhaps you should try some spelling variations:
thuat lap » thuat lanh, thuat xay, thuat bai
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
toan cau » toan cao, toan ban, toan tap
co sach » bo sach, cuon sach, hoc sach
hieu ve » hieu va, hieu van
va tinh » may tinh
cau tre » cau tren, cau treo, cau tra
ve cac » va cac, vien cac
x hoi » xa hoi, x ho, 5 hoi
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: ((co sach) or (thuat lap)) ky nang ((x hoi) OR (o hoi)). hieu ve cac nuoc va tinh toan cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (thuat lap)) ky nang ((x hoi) OR (o hoi)). hieu ve cac nuoc va tinh toan cau tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) or (thuat lap)) ky nang ((x hoi) OR (o hoi)). hieu ve cac nuoc va tinh toan cau tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) or (thuat lap)) ky nang ((x hoi) OR (o hoi)). hieu ve cac nuoc va tinh toan cau tre*.