Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
hieu van » thien van, lieu va, hieu ve
tinh di » tinh doi, trinh di, tinh da
va tinh » may tinh
nam xuc » cam xuc, nam xua, nam thuc
hieu va » lieu va, hieu qua
cua tre » cua te, cuu tre, cua triet
tang ma » mang may, tang van
tang xa » trang xa, lang xa, tang ha
xuc va » duc va, tuc va, luc va
di cua » dai cua, doi cua, de cua

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