Perhaps you should try some spelling variations:
pham thuc » phap thuc, pham chuc, nham thuc
thu sach » thuat sach, thuoc sach, thu hoach
hanh doi » thanh doi, hanh noi, hang doi
hieu van » thien van, lieu va, hieu ve
tu sach » su sach, te sach, tu cach
doi cua » dai cua, hoi cua, dong cua
va hanh » van hanh, va thanh, va danh
thuc va » thuc vat, thuc dan, thuc day
cua tre » cua te, cuu tre, cua triet
hieu va » lieu va, hieu qua
nang xa » nang x, lang xa, nang ma

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) or (thu sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) pham thuc va hanh doi cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thu sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) pham thuc va hanh doi cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thu sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) pham thuc va hanh doi cua tre".
• Adding a wildcard symbol may retrieve word variants: ((tu sach) or (thu sach)) ky nang xa hoi. ((hieu van) OR (hieu va)) pham thuc va hanh doi cua tre*.