Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
nhan luc » nang luc
nang ma » tang ma, sang ma, nang cao
hieu ve » hieu va, hieu van
ve nhan » ve nha, de nhan, va nhan
va hanh » van hanh, va thanh, va danh
hanh ve » hanh vi, hanh va, hanh kem
sac ky » cac ky
luc va » duc va, tuc va, loc va
ve cau » ke cau, va cau, ve cac

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sac ky) OR (sai ky)) ((nang ma) or (nang x)) hoi. hieu ve nhan luc va hanh ve cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sac ky) OR (sai ky)) ((nang ma) OR (nang x)) hoi. hieu ve nhan luc va hanh ve cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sac ky) OR (sai ky)) ((nang ma) or (nang x)) hoi. hieu ve nhan luc va hanh ve cau tren".
• Adding a wildcard symbol may retrieve word variants: tu ((sac ky) OR (sai ky)) ((nang ma) or (nang x)) hoi. hieu ve nhan luc va hanh ve cau tren*.