Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
sinh dai » sinh thai, si dai, sinh vat
nang xa » nang x, nang ma, mang xa
lang xa » lang ha, dang xay, lang van
va chat » van chat, cao chat, hoa chat
va sinh » va kinh, va tinh, vi sinh
cua tre » cua te, cuu tre, cua triet
xuc va » duc va, tuc va, luc va

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