Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
sinh dai » sinh thai, si dai, sinh vat
tu sach » su sach, te sach, tu cach
nang xa » nang x, lang xa, nang ma
va chat » van chat, cao chat, hoa chat
va sinh » va kinh, va tinh, vi sinh
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang
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) OR (tu sach)) y nang 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) OR (tu sach)) y nang 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) OR (tu sach)) y nang xa hoi. hieu ((va chat) or (va phat)) xuc va sinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) y nang xa hoi. hieu ((va chat) or (va phat)) xuc va sinh dai cua tre*.