Perhaps you should try some spelling variations:
thuoc sach » hoc sach, nuoc sach, thuat sach
hieu viec » nhieu viec, hieu ve, sieu viet
lang cua » mang cua, hang cua, long cua
viec nam » viet nam, viec lam, vien nam
tu sach » thu sach, su sach, te sach
lang ca » lang cao, hang ca, lang ha
nam tan » nam dan, nam tai, nam van
tan hoa » van hoa, tap hoa, tan ha
nang ma » tang ma, sang ma, nang cao
cua tre » cua te, cuu tre, cua triet
y nang » ky nang, ly nang, v nang

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) or (thuoc sach)) y nang ma hoa. hieu viec nam tan hoa ((lang ca) OR (lang cua)) cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((tu sach) OR (thuoc sach)) y nang ma hoa. hieu viec nam tan hoa ((lang ca) OR (lang cua)) cua tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((tu sach) or (thuoc sach)) y nang ma hoa. hieu viec nam tan hoa ((lang ca) OR (lang cua)) cua tre*".