Perhaps you should try some spelling variations:
trinh viet » ninh viet, trinh vat
cau tren » cu tren, dau tren, ca tren
trinh vi » trinh va, trinh ve, trinh van
tu sach » thu sach, su sach, te sach
cam cuc » cam xuc, cham cuu, pham cuc
hieu ve » hieu va, hieu van
lang xa » lang ha, dang xay, lang van
sach o » sach lo, sac o, sach y
o lang » hoa lang, hoi lang

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 o lang xa hoi. hieu ve ((cam cuc) or (cap cuu)) ban ((trinh vi) or (trinh viet)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach o lang xa hoi. hieu ve ((cam cuc) OR (cap cuu)) ban ((trinh vi) OR (trinh viet)) cau tren.
• Adding a wildcard symbol may retrieve word variants: tu sach o lang xa hoi. hieu ve ((cam cuc) or (cap cuu)) ban ((trinh vi) or (trinh viet)) cau tren*.