Perhaps you should try some spelling variations:
tu sach » thu sach, su sach, te sach
tang xa » trang xa, tang ma, lang xa
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cua triet, dua tren
cuu tre » cau tren, cau treo
co viet » so viet, o viet, hoc viet
y tang » ky tang, 6 tang, 7 tang
va cau » van cau, va cac, va dau
cau tu » dau tu, cau truc

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu sach y tang xa hoi. lieu va cau tu va hanh vi ((((cua tre) OR (cuu tre))) or (co viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y tang xa hoi. lieu va cau tu va hanh vi ((((cua tre) OR (cuu tre))) OR (co viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y tang xa hoi. lieu va cau tu va hanh vi ((((cua tre) OR (cuu tre))) or (co viet))".
• Adding a wildcard symbol may retrieve word variants: tu sach y tang xa hoi. lieu va cau tu va hanh vi ((((cua tre) OR (cuu tre))) or (co viet))*.