Perhaps you should try some spelling variations:
phan thi » pham thi, tran thi, phan tu
van phan » van phong, van thanh, luan phan
vu sach » vu bach, su sach, vu khach
sach ky » sac ky, sach y, sach ty
duc van » duc va, duc tan, duc manh
cau duc » cao duc, cau luc, chu duc
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
va cau » van cau, va cac, va dau
cuc tu » luc tu, duc tu, cac tu
cuc du » cac du

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

• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ky ((nang xa) OR (lang xa)) hoi. hieu va cau duc van phan thi ((cuc tu) OR (cuc du))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "vu sach ky ((nang xa) or (lang xa)) hoi. hieu va cau duc van phan thi ((cuc tu) OR (cuc du))~".
• Adding a wildcard symbol may retrieve word variants: vu sach ky ((nang xa) or (lang xa)) hoi. hieu va cau duc van phan thi ((cuc tu) OR (cuc du))*.