Perhaps you should try some spelling variations:
manh thanh » danh thanh, minh thanh, manh thang
doc sach » hoc sach, toc sach, nuoc sach
hieu van » hieu va, thien van, lieu va
thanh vi » hanh vi, thanh va, thanh ve
duc manh » suc manh, duc anh, duc minh
dang xay » dang van, van xay
cua tre » cua te, cua triet, dua tren
cam duc » cam xuc, cao duc, pham duc
van cam » van nam, van lam, van cau
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, lang van
cuu tre » cau tren, cau treo

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ky ((lang xa) OR (dang xay)) hoi. hieu van cam duc manh thanh vi ((cua tre) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ky ((lang xa) OR (dang xay)) hoi. hieu van cam duc manh thanh vi ((cua tre) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ky ((lang xa) OR (dang xay)) hoi. hieu van cam duc manh thanh vi ((cua tre) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: doc sach ky ((lang xa) OR (dang xay)) hoi. hieu van cam duc manh thanh vi ((cua tre) or (cuu tre))*.