Perhaps you should try some spelling variations:
van trinh » van thinh, van tinh, dan trinh
thu sach » tu sach, thuat sach, thuoc sach
va trinh » va tinh, lap trinh, qua trinh
lang xa » lang ha, dang xay, lang van
hieu ve » hieu van
hieu va » lieu va, hieu qua
dai cuu » dai cua, dai huu
cuu tre » cua tre, cau tren, cau treo
y lang » o lang, _ lang, tay lang
am hoc » ad hoc

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y lang xa hoi. ((hieu ve) OR (hieu va)) am hoc ((va trinh) or (van trinh)) dai cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y lang xa hoi. ((hieu ve) OR (hieu va)) am hoc ((va trinh) OR (van trinh)) dai cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y lang xa hoi. ((hieu ve) OR (hieu va)) am hoc ((va trinh) or (van trinh)) dai cuu tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y lang xa hoi. ((hieu ve) OR (hieu va)) am hoc ((va trinh) or (van trinh)) dai cuu tre*.