Perhaps you should try some spelling variations:
tu tieng » luc tieng, tu tuong, tu trong
hanh hai » thanh hai, nhanh hai, hang hai
van hanh » van thanh, ban hanh, van anh
pham duy » pham duc
hieu ve » hieu va, hieu van
ve pham » vi pham, v pham, ve phan
sach ty » sach tu, sach thu, xach tay
duy van » duy vat, dung van
su tien » su kien, su hien, dau tien
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: tu ((sach ty) or (sach y)) nang x hoi. hieu ve pham duy van hanh hai ((su tien) OR (tu tieng))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu ((sach ty) OR (sach y)) nang x hoi. hieu ve pham duy van hanh hai ((su tien) OR (tu tieng))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu ((sach ty) or (sach y)) nang x hoi. hieu ve pham duy van hanh hai ((su tien) OR (tu tieng))*".