Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
van hanh » van thanh, ban hanh, van anh
cham sac » cham soc, pham sach, cap sac
cau tren » cu tren, dau tren, ca tren
nang xa » nang x, lang xa, mang xa
hieu va » lieu va, hieu qua
va cham » va chat, va tham
tu sach » su sach, te sach, tu cach
sac van » cac van, san van, sat van
nang ma » tang ma, sang ma, nang cao
vi cau » va cau, ve cau, di cau

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((thu sach) or (tu sach)) ty ((nang xa) or (nang ma)) hoi. hieu va cham sac van hanh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) ty ((nang xa) OR (nang ma)) hoi. hieu va cham sac van hanh vi cau tren.
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (tu sach)) ty ((nang xa) or (nang ma)) hoi. hieu va cham sac van hanh vi cau tren*.