Perhaps you should try some spelling variations:
than duc » tran duc, phan duc, than doc
hieu van » hieu va, thien van, lieu va
tham duc » pham duc, tham du, thach duc
hanh lai » hanh lam, hanh tai, thanh lap
te sach » toc sach
cuu tre » cau tren, cau treo
va hanh » van hanh, va thanh, va danh
cua tre » cua te, cua triet, dua tren
sach ty » sach y, sach tu, sach thu
cao hoi » cau hoi, co hoi, cao hoc
ty nang » ky nang, ty xang, ty hang

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

• Performing a fuzzy search may retrieve terms with similar spellings: te sach ty nang cao hoi. hieu van ((tham duc) or (than duc)) va hanh lai ((cuu tre) OR (cua tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: te sach ty nang cao hoi. hieu van ((tham duc) OR (than duc)) va hanh lai ((cuu tre) OR (cua tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "te sach ty nang cao hoi. hieu van ((tham duc) or (than duc)) va hanh lai ((cuu tre) OR (cua tre))".
• Adding a wildcard symbol may retrieve word variants: te sach ty nang cao hoi. hieu van ((tham duc) or (than duc)) va hanh lai ((cuu tre) OR (cua tre))*.