Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thi hang » thi hanh, thi nang, thi hong
cham tuc » nham thuc, tham thuc, cham soc
sach thi » sach thu, sach tai, sach thieu
so sach » so sanh, bo sach, co sach
tai cuu » tai buu, tai cua, thai cua
xa hanh » xa thanh, xa khanh, va hanh
hieu va » lieu va, hieu qua
va hoi » xa hoi, va hoc, va hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: so sach thi hang va hoi. hieu va ((cham tuc) or (pham thuc)) xa hanh ((tai cuu) OR (tai cuc)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: so sach thi hang va hoi. hieu va ((cham tuc) OR (pham thuc)) xa hanh ((tai cuu) OR (tai cuc)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "so sach thi hang va hoi. hieu va ((cham tuc) or (pham thuc)) xa hanh ((tai cuu) OR (tai cuc)) tre".
• Adding a wildcard symbol may retrieve word variants: so sach thi hang va hoi. hieu va ((cham tuc) or (pham thuc)) xa hanh ((tai cuu) OR (tai cuc)) tre*.