Perhaps you should try some spelling variations:
mlang chai » cang chai, lang hai, lang thai
lang chai » lang ha, lang cua, lang phi
quoc ban » quoc bao, quoc lan, quoc quan
tu sach » thu sach, su sach, te sach
cuu tre » cua tre, cau tren, cau treo
hieu ve » hieu va, hieu van
ly nang » ky nang, ly hang, ly vang
y nang » ky nang, v nang, may nang
ma hoi » mai hoi, xa hoi, ma hoa
ve han » ve hanh, ve phan, ve ban

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 ((y nang) OR (ly nang)) ma hoi. hieu ve han quoc ban ((lang chai) or (mlang chai)) cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: tu sach ((y nang) OR (ly nang)) ma hoi. hieu ve han quoc ban ((lang chai) OR (mlang chai)) cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "tu sach ((y nang) OR (ly nang)) ma hoi. hieu ve han quoc ban ((lang chai) or (mlang chai)) cuu tre".
• Adding a wildcard symbol may retrieve word variants: tu sach ((y nang) OR (ly nang)) ma hoi. hieu ve han quoc ban ((lang chai) or (mlang chai)) cuu tre*.