Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
thu sach » tu sach, thuat sach, thuoc sach
cham duc » cham soc, pham duy, phan duc
van phan » van phong, van thanh, luan phan
phan lai » phan loai, phan lap, phan lan
nam viet » pham viet, lam viec, bac viet
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
lai nam » loai nam, hai nam, mai nam
x hoi » xa hoi, o hoi, 5 hoi

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 ty nang ((x hoi) or (x ho)). hieu van ((cham duc) OR (pham duc)) van phan lai nam viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach ty nang ((x hoi) OR (x ho)). hieu van ((cham duc) OR (pham duc)) van phan lai nam viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach ty nang ((x hoi) or (x ho)). hieu van ((cham duc) OR (pham duc)) van phan lai nam viet".
• Adding a wildcard symbol may retrieve word variants: thu sach ty nang ((x hoi) or (x ho)). hieu van ((cham duc) OR (pham duc)) van phan lai nam viet*.