Perhaps you should try some spelling variations:
su triet » su viet, su tien, ve triet
van hanh » van thanh, ban hanh, van anh
vu sach » vu bach, su sach, vu khach
luc van » luoc van, luu van, duc van
cam luc » cam xuc, cau luc
hieu ve » hieu va, hieu van
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, sang tao, mang may
nang ma » tang 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: vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cam luc van hanh vi ((su triet) or (hoa viet))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cam luc van hanh vi ((su triet) OR (hoa viet)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cam luc van hanh vi ((su triet) or (hoa viet))".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang ma) OR (sang ma)) hoi. hieu ve cam luc van hanh vi ((su triet) or (hoa viet))*.