Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
van hanh » van thanh, ban hanh, van anh
su sach » so sach, vu sach
va hanh » va thanh, va danh, ban hanh
va pham » van pham, va phat, va phap
sach ky » sac ky, sach y, sach ty
lang xa » lang ha, dang xay, lang van
mang xa » mang may, dang xay, mang cua
cua tre » cua te, cuu tre, cua triet
ve cua » le cua, de cua, te cua

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach ky ((mang xa) or (lang xa)) hoi. lieu va pham thuc ((va hanh) OR (van hanh)) ve cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((mang xa) OR (lang xa)) hoi. lieu va pham thuc ((va hanh) OR (van hanh)) ve cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((mang xa) or (lang xa)) hoi. lieu va pham thuc ((va hanh) OR (van hanh)) ve cua tre".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((mang xa) or (lang xa)) hoi. lieu va pham thuc ((va hanh) OR (van hanh)) ve cua tre*.