Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
thu sach » tu sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
hac duc » hoc duc, ha duc, thach duc
hang di » hang doi, hang vi, hang dien
hanh di » hanh vi, hanh de, danh di
duc van » duc va, duc tan, duc manh
van hac » van hoc, van ha, van hai
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
x hoi » xa hoi, o hoi, x ho

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 (thuat sach)) ty nang x hoi. hieu van hac duc van ((hanh di) OR (hang di)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (thuat sach)) ty nang x hoi. hieu van hac duc van ((hanh di) OR (hang di)) cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) or (thuat sach)) ty nang x hoi. hieu van hac duc van ((hanh di) OR (hang di)) cua tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) or (thuat sach)) ty nang x hoi. hieu van hac duc van ((hanh di) OR (hang di)) cua tre*.