Perhaps you should try some spelling variations:
manh thanh » danh thanh, minh thanh, manh thang
thanh dai » thanh hai, thanh tai, thanh dat
hieu van » hieu va, thien van, lieu va
nam thuc » nam thuoc, am thuc, nam thu
nam duc » nam duoc, pham duc, nam buoc
tu sach » thu sach, su sach, te sach
sach ty » sach y, sach tu, sach thu
long ha » dong ha, cong ha, dong hoa
lang xa » lang ha, dang xay, lang van
cua tre » cua te, cuu tre, cua triet

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 ty ((lang xa) or (long ha)) hoi. hieu van ((nam duc) or (nam thuc)) manh thanh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty ((lang xa) OR (long ha)) hoi. hieu van ((nam duc) OR (nam thuc)) manh thanh dai cua tre.
• Adding a wildcard symbol may retrieve word variants: tu sach ty ((lang xa) or (long ha)) hoi. hieu van ((nam duc) or (nam thuc)) manh thanh dai cua tre*.