Perhaps you should try some spelling variations:
tham thuc » nham thuc, pham thuc, tam thuc
cau tren » cu tren, dau tren, ca tren
tham luc » than luc, tham nuoc, nhan luc
tai cau » tai cac, tai cao
dan tai » van tai, dan thi, han tai
lang xa » dang xay, lang van
lang ha » long ha
sac ky » cac ky, sai ky
va dan » ca dan, va dao, va dau
te sac » te sach, te cac, te san

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sac ky ((lang xa) or (lang ha)) hoi. lieu va ((tham luc) OR (tham thuc)) va dan tai cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sac ky ((lang xa) OR (lang ha)) hoi. lieu va ((tham luc) OR (tham thuc)) va dan tai cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sac ky ((lang xa) or (lang ha)) hoi. lieu va ((tham luc) OR (tham thuc)) va dan tai cau tren".
• Adding a wildcard symbol may retrieve word variants: te sac ky ((lang xa) or (lang ha)) hoi. lieu va ((tham luc) OR (tham thuc)) va dan tai cau tren*.