Perhaps you should try some spelling variations:
thanh luc » thanh luu, than luc, nhan luc
van thanh » ban thanh, van tuan
hieu van » hieu va, thien van, lieu va
dinh tai » dinh toai, dinh tri, dinh thi
danh tai » doanh tai, hanh tai, anh tai
tu sach » thu sach, su sach, te sach
sang ma » tang ma, sang tao, mang may
nang ma » tang ma, nang cao, mang may
cua tre » cua te, cuu tre, cua triet
luc va » duc va, tuc va, loc va

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 ((nang ma) OR (sang ma)) hoi. hieu van thanh luc va ((danh tai) or (dinh tai)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach y ((nang ma) OR (sang ma)) hoi. hieu van thanh luc va ((danh tai) OR (dinh tai)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach y ((nang ma) OR (sang ma)) hoi. hieu van thanh luc va ((danh tai) or (dinh tai)) cua tre".
• Adding a wildcard symbol may retrieve word variants: tu sach y ((nang ma) OR (sang ma)) hoi. hieu van thanh luc va ((danh tai) or (dinh tai)) cua tre*.