Perhaps you should try some spelling variations:
hieu van » hieu va, thien van, lieu va
su sach » so sach
dinh ly » sinh ly, dinh le, trinh ly
va dinh » van dinh, va kinh, va tinh
cac dac » cac dan, cac dai, cac bac
cac duc » cac du, cao duc, cac nuoc
nang ma » tang ma, sang ma, nang cao
vu sach » vu bach, vu khach
ma hoi » mai hoi, xa hoi, ma hoa
y nang » ky nang, ly nang, v nang
ly cua » le cua
cua te » cua tu

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

• Performing a fuzzy search may retrieve terms with similar spellings: ((su sach) or (vu sach)) y nang ma hoi. hieu van ((cac duc) OR (cac dac)) va dinh ly cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((su sach) OR (vu sach)) y nang ma hoi. hieu van ((cac duc) OR (cac dac)) va dinh ly cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((su sach) or (vu sach)) y nang ma hoi. hieu van ((cac duc) OR (cac dac)) va dinh ly cua te".
• Adding a wildcard symbol may retrieve word variants: ((su sach) or (vu sach)) y nang ma hoi. hieu van ((cac duc) OR (cac dac)) va dinh ly cua te*.