Perhaps you should try some spelling variations:
thanh lap » thanh san, thanh hai, thanh van
cam viet » cham viet, ca viet, cao viet
phan lap » phan dau
cham duc » pham duc, cham soc, pham duy
hieu van » thien van, lieu va, hieu ve
hieu va » lieu va, hieu qua
sach ty » sach y, sach tu, sach thu
duc van » duc va, duc tan, duc manh
ty nang » ky nang, ty xang, ty hang
tu sach » thu sach, su sach, te sach
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: tu sach ty nang x hoi. ((hieu van) OR (hieu va)) cham duc van ((thanh lap) or (phan lap)) cam viet~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ty nang x hoi. ((hieu van) OR (hieu va)) cham duc van ((thanh lap) OR (phan lap)) cam viet.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ty nang x hoi. ((hieu van) OR (hieu va)) cham duc van ((thanh lap) or (phan lap)) cam viet".
• Adding a wildcard symbol may retrieve word variants: tu sach ty nang x hoi. ((hieu van) OR (hieu va)) cham duc van ((thanh lap) or (phan lap)) cam viet*.