Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
cau thuc » cuu thuc, can thuc, cau phuc
dan hanh » dang hanh, dan khanh, dan thanh
tu sach » thu sach, su sach, te sach
hanh ve » hanh vi, hanh va, hanh kem
y nang » ky nang, ly nang, may nang
v nang » va nang, vu nang, van nang
ve cua » le cua, de cua, te cua
cua te » cua tu

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 ((y nang) or (v nang)) xa hoi. hieu van ((cau thuc) OR (cau truc)) dan hanh ve cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (v nang)) xa hoi. hieu van ((cau thuc) OR (cau truc)) dan hanh ve cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) or (v nang)) xa hoi. hieu van ((cau thuc) OR (cau truc)) dan hanh ve cua te".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) or (v nang)) xa hoi. hieu van ((cau thuc) OR (cau truc)) dan hanh ve cua te*.