Perhaps you should try some spelling variations:
thuat sac » thuat sach, thuat san, thuat tac
nam truoc » nam thuoc, lam truoc, nam truc
truoc va » truc va, thuoc va, truong va
va danh » va dinh, va dan, va hanh
doi hoa » doi hoac, doi hoat, do hoa
hieu va » lieu va, hieu qua
nang xa » lang xa, nang ma, mang xa
sac ky » cac ky, sai ky
di hoa » dai hoa, do hoa, bi hoa
va nam » van nam, ha nam, va nay

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sac ky ((nang xa) OR (nang x)) hoi. hieu va nam truoc va danh ((di hoa) or (doi hoa)) viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sac ky ((nang xa) OR (nang x)) hoi. hieu va nam truoc va danh ((di hoa) OR (doi hoa)) viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sac ky ((nang xa) OR (nang x)) hoi. hieu va nam truoc va danh ((di hoa) or (doi hoa)) viet".
• Adding a wildcard symbol may retrieve word variants: thuat sac ky ((nang xa) OR (nang x)) hoi. hieu va nam truoc va danh ((di hoa) or (doi hoa)) viet*.