Perhaps you should try some spelling variations:
thuat lap » thuat lanh, thuat xay, thuat bai
cac nuoc » cap nuoc, hoc nuoc, dat nuoc
toan cuu » toan cau, toan cua, toan cao
co sach » bo sach, cuon sach, hoc sach
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
ve cac » va cac, vien cac
x hoi » xa hoi, o hoi, x ho

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. hieu ve cac nuoc ((va tinh) OR (may tinh)) toan cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((co sach) OR (thuat lap)) ky nang x hoi. hieu ve cac nuoc ((va tinh) OR (may tinh)) toan cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((co sach) or (thuat lap)) ky nang x hoi. hieu ve cac nuoc ((va tinh) OR (may tinh)) toan cuu tre".
• Adding a wildcard symbol may retrieve word variants: ((co sach) or (thuat lap)) ky nang x hoi. hieu ve cac nuoc ((va tinh) OR (may tinh)) toan cuu tre*.