Perhaps you should try some spelling variations:
thien hach » thien thanh, hien hanh
hanh trinh » canh tranh, hanh chinh
hoc thien » hoc hien, hoc thieu, hoc thiet
trinh cua » tinh cua, trinh luat, trinh quan
cua thong » cua thuong, cua khong, cua tong
tac vang » cac van, tac dung, tac dong
toan can » toan ban, toan cao, toan cau
tac can » tac van, tac quan, tac danh

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc thien hach - hanh trinh cua thong thong ((((tac can) OR (tac vang))) or (toan can)) cau~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc thien hach - hanh trinh cua thong thong ((((tac can) OR (tac vang))) OR (toan can)) cau.
• The words AND, OR and NOT may confuse the search; try adding quotes: "hoc thien hach - hanh trinh cua thong thong ((((tac can) OR (tac vang))) or (toan can)) cau".
• Adding a wildcard symbol may retrieve word variants: hoc thien hach - hanh trinh cua thong thong ((((tac can) OR (tac vang))) or (toan can)) cau*.