Perhaps you should try some spelling variations:
manh thanh » danh thanh, minh thanh, manh thang
thanh lap » thanh san, phan lap, thanh hai
sach thu » sach thue, sach thieu, sach tham
hieu van » hieu va, thien van, lieu va
duc manh » suc manh, duc anh, duc minh
sach ty » sach tu, xach tay, sach hay
lang xa » lang ha, dang xay, lang van
nam duc » nam duoc, pham duc, nam thuc
lap cua » lai cua, tap cua, lam cua
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) OR (sach thu))) or (sach y)) lang xa hoi. hieu van nam duc manh thanh lap cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((((sach ty) OR (sach thu))) OR (sach y)) lang xa hoi. hieu van nam duc manh thanh lap cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((((sach ty) OR (sach thu))) or (sach y)) lang xa hoi. hieu van nam duc manh thanh lap cua tre".
• Adding a wildcard symbol may retrieve word variants: tu ((((sach ty) OR (sach thu))) or (sach y)) lang xa hoi. hieu van nam duc manh thanh lap cua tre*.