Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
gian cua » gian xu, ban cua
tat hanh » tat thanh, nhat hanh, dat khanh
thuc tat » thuc vat, thuc tap, thuc tai
su sach » so sach, vu sach
via cua » gia cua, giau cua, rija cua
sach ky » sac ky, sach y, sach ty
hieu ve » hieu va, hieu van
tang ma » mang may, tang van
nang ma » sang ma, nang cao, mang may
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: su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cam thuc tat hanh ((via cua) OR (gian cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang ma) OR (tang ma)) hoi. hieu ve cam thuc tat hanh ((via cua) OR (gian cua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cam thuc tat hanh ((via cua) OR (gian cua)) tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang ma) or (tang ma)) hoi. hieu ve cam thuc tat hanh ((via cua) OR (gian cua)) tre*.