Perhaps you should try some spelling variations:
tinh dai » trinh dai, tinh hai, tinh doi
lang van » dang van, tang van, hoang van
tu sach » thu sach, su sach, te sach
tinh da » tinh va, tinh gia, tinh lao
hieu ve » hieu va, hieu van
cuu tre » cua tre, cau tren, cau treo
lang xa » lang ha, dang xay
am hoc » ad hoc
ve am » va am

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 ((lang xa) or (lang van)) hoi. hieu ve am hoc va ((tinh dai) or (tinh da)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((lang xa) OR (lang van)) hoi. hieu ve am hoc va ((tinh dai) OR (tinh da)) cuu tre.
• Adding a wildcard symbol may retrieve word variants: tu sach y ((lang xa) or (lang van)) hoi. hieu ve am hoc va ((tinh dai) or (tinh da)) cuu tre*.