Perhaps you should try some spelling variations:
dieu tra » dieu tri, kiem tra, dieu cua
tu sach » thu sach, su sach, te sach
sach ky » sac ky, sach y, sach ty
ho ngoc » do ngoc, ho nuoc, lo ngoc
nang xa » lang xa, nang ma, mang xa
tra tre » tran tren, tran tri, tran tro
va dap » va dao, va dau
ca dan » cac dan, ca dao
va ho » va hoc, va hoa, va hoi

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 ky ((nang xa) OR (nang x)) hoi. lieu va ho ngoc ((va dap) or (ca dan)) dieu tra tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ky ((nang xa) OR (nang x)) hoi. lieu va ho ngoc ((va dap) OR (ca dan)) dieu tra tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ky ((nang xa) OR (nang x)) hoi. lieu va ho ngoc ((va dap) or (ca dan)) dieu tra tre*".