Perhaps you should try some spelling variations:
cau tren » cu tren, ca tren, cau treo
dau tren » dau tien, dat tren, dau tieng
su sach » so sach
vu sach » vu bach, vu khach
ty nang » ky nang, ty xang, ty hang
nang xa » nang x, lang xa, nang ma
hieu ve » hieu va, hieu van
ve giao » te giao, viet giao, van giao
va hanh » van hanh, va thanh, va danh

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) or (vu sach)) ty nang xa hoi. hieu ve giao duc va hanh kem ((cau tren) OR (dau tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) ty nang xa hoi. hieu ve giao duc va hanh kem ((cau tren) OR (dau tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) ty nang xa hoi. hieu ve giao duc va hanh kem ((cau tren) OR (dau tren))".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) ty nang xa hoi. hieu ve giao duc va hanh kem ((cau tren) OR (dau tren))*.