Perhaps you should try some spelling variations:
cam thuc » am thuc, nam thuc, cam thu
vat hanh » vat thanh, van hanh, va hanh
cau tren » dau tren, cau treo, cau tieng
su sach » so sach, vu sach
hieu ve » hieu va, hieu van
hanh da » hanh dao, hanh dua, hanh va
ca tren » la tren, co tren, xa tren
cu tren » tu tren, dua tren
y nang » ky nang, ly nang, v nang
ve cam » ve cham, ve cac, va cam
x hoi » xa hoi, o hoi, x ho

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 y nang x hoi. hieu ve cam thuc vat hanh da ((((cau tren) OR (ca tren))) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach y nang x hoi. hieu ve cam thuc vat hanh da ((((cau tren) OR (ca tren))) OR (cu tren)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach y nang x hoi. hieu ve cam thuc vat hanh da ((((cau tren) OR (ca tren))) or (cu tren))".
• Adding a wildcard symbol may retrieve word variants: su sach y nang x hoi. hieu ve cam thuc vat hanh da ((((cau tren) OR (ca tren))) or (cu tren))*.