Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
va thuat » ky thuat, ki thuat, va thuc
lang van » dang van, hoang van, giang van
tang van » dang van, hoang van, trong van
tinh van » trinh van, dinh van, tinh va
van cau » van dau, van hau, van chat
va tinh » may tinh
va cham » va chat, va tham
cau tre » cau tren, cau treo, cau tra

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 van) OR (tang van)) hoi. hieu ((va cham) or (va thuat)) duc va tinh van cau tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((lang van) OR (tang van)) hoi. hieu ((va cham) OR (va thuat)) duc va tinh van cau tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((lang van) OR (tang van)) hoi. hieu ((va cham) or (va thuat)) duc va tinh van cau tre".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((lang van) OR (tang van)) hoi. hieu ((va cham) or (va thuat)) duc va tinh van cau tre*.