Perhaps you should try some spelling variations:
dieu tra » dieu tri, kiem tra, dieu cua
tham luc » than luc, tham nuoc, tham thuc
tu sach » thu sach, su sach, te sach
va danh » va dinh, va dan, va hanh
va tham » van tham, va cham, va thanh
sach va » sach xa, sach ha, sach dao
hieu va » lieu va, hieu qua
nang ma » tang ma, sang ma, nang cao
nang xa » nang x, lang xa, mang xa
luc va » duc va, tuc va, loc va
de cua » le cua, te cua, dieu cua

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 va ((nang xa) or (nang ma)) hoi. hieu va tham luc va danh ((de cua) or (dieu tra)) vat~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach va ((nang xa) OR (nang ma)) hoi. hieu va tham luc va danh ((de cua) OR (dieu tra)) vat.
• Adding a wildcard symbol may retrieve word variants: tu sach va ((nang xa) or (nang ma)) hoi. hieu va tham luc va danh ((de cua) or (dieu tra)) vat*.