Perhaps you should try some spelling variations:
sach thi » sach thu, sach tai, sach tham
cam thuc » am thuc, nam thuc, cam thu
hanh xa » hanh va, hanh ma, hanh xu
hieu ve » hieu va, hieu van
thuc va » thuc vat, thuc dan, thuc day
va danh » va dinh, va dan, va hanh
nam van » nam dan, pham van, nam danh
ve cam » ve cham, ve cac, va cam

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 thi) or (sach thieu)) hanh xa hoi. hieu ve cam thuc va danh ((nam van) OR (nam va)) triet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach thi) OR (sach thieu)) hanh xa hoi. hieu ve cam thuc va danh ((nam van) OR (nam va)) triet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach thi) or (sach thieu)) hanh xa hoi. hieu ve cam thuc va danh ((nam van) OR (nam va)) triet".
• Adding a wildcard symbol may retrieve word variants: tu ((sach thi) or (sach thieu)) hanh xa hoi. hieu ve cam thuc va danh ((nam van) OR (nam va)) triet*.