Perhaps you should try some spelling variations:
cau tren » cu tren, dau tren, ca tren
hieu van » hieu va, thien van, lieu va
cac thoi » cac toi, cac hop, cac tro
tinh vi » trinh vi, tinh voi, tinh va
va tinh » may tinh
cac tuc » cac toc, cac tu, cac tac
hanh ky » hanh kem
vu hanh » vu khanh, vu thanh, du hanh
tang xa » trang xa, lang xa, tang ha
tang ma » mang may, tang van
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: vu hanh ky ((tang xa) OR (tang ma)) hoi. hieu van ((cac tuc) or (cac thoi)) va tinh vi cau tren~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu hanh ky ((tang xa) OR (tang ma)) hoi. hieu van ((cac tuc) OR (cac thoi)) va tinh vi cau tren*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu hanh ky ((tang xa) OR (tang ma)) hoi. hieu van ((cac tuc) or (cac thoi)) va tinh vi cau tren*".