Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
phap thuc » phap thu, phap hoc, phap tu
nang doc » nang luc
thanh di » thanh doi, thanh de, thanh do
ve phap » va phap, de phap, ve phan
hieu ve » hieu va, hieu van
sach ky » sach y, sach ty, sach kem
nang co » nang cao, nang noi, nang hoc
sac ky » cac ky, sai ky
di cua » dai cua, doi cua, de cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu ((sach ky) or (sac ky)) ((nang co) OR (nang doc)) hoi. hieu ve phap thuc vat thanh di cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu ((sach ky) OR (sac ky)) ((nang co) OR (nang doc)) hoi. hieu ve phap thuc vat thanh di cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu ((sach ky) or (sac ky)) ((nang co) OR (nang doc)) hoi. hieu ve phap thuc vat thanh di cua te".
• Adding a wildcard symbol may retrieve word variants: thu ((sach ky) or (sac ky)) ((nang co) OR (nang doc)) hoi. hieu ve phap thuc vat thanh di cua te*.