Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
phan duc » pham duc, phan tu, phan dau
hoc sach » hoc sinh, hoc cac, hoc anh
tuan tai » toan tai, quan tai, tan tai
tuan lai » xuan lai, tuong lai, thuan loi
duc van » duc va, duc tan, duc manh
va phan » van phan, va phat, va phap
hieu va » lieu va, hieu qua
chau te » chau tho
nang o » nang co, nang ho, nang ro
o hoi » co hoi, o hoc, o hai

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) or (hoc sach)) ky nang o hoi. hieu va phan duc van ((tuan lai) OR (tuan tai)) chau te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (hoc sach)) ky nang o hoi. hieu va phan duc van ((tuan lai) OR (tuan tai)) chau te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (hoc sach)) ky nang o hoi. hieu va phan duc van ((tuan lai) OR (tuan tai)) chau te".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (hoc sach)) ky nang o hoi. hieu va phan duc van ((tuan lai) OR (tuan tai)) chau te*.