Perhaps you should try some spelling variations:
hanh trinh » canh tranh, hanh chinh
hanh tinh » nhanh tinh, thanh tinh, canh tinh
cau tren » cu tren, dau tren, ca tren
va cham » va chat, va tham
soc ban » hoc ban, coc ban, so ban
te sach » toc sach
sach ty » sach y, sach tu, sach thu
nang ma » tang ma, sang ma, nang cao
hieu va » lieu va, hieu qua

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty ((nang ma) or (nang x)) hoi. hieu va cham soc ban ((hanh tinh) OR (hanh trinh)) cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty ((nang ma) OR (nang x)) hoi. hieu va cham soc ban ((hanh tinh) OR (hanh trinh)) cau tren.
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty ((nang ma) or (nang x)) hoi. hieu va cham soc ban ((hanh tinh) OR (hanh trinh)) cau tren".
• Adding a wildcard symbol may retrieve word variants: te sach ty ((nang ma) or (nang x)) hoi. hieu va cham soc ban ((hanh tinh) OR (hanh trinh)) cau tren*.