Perhaps you should try some spelling variations:
thiet hach » thien hach, thuyet hach, thiet hai
hoc thiet » hoc thieu, hoc thuyet, hoc hien
ban huong » bang phuong, ban hang, anh huong
tang cua » hang cua, tang luan, thong cua
mang cua » manh cua, dung cua, ban cua
than cau » phan cau, than cap, thanh chau
toan cau » toan cao, toan ban, toan tap

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

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