Perhaps you should try some spelling variations:
doc sach » hoc sach, toc sach, nuoc sach
sinh dai » sinh thai, si dai, sinh vat
xac sinh » xac dinh, xa sinh, xuan sinh
thai tuc » thai thuc, thai thuy, thai hoc
tham tuc » tham thuc, nham thuc, pham thuc
sach ty » sach y, sach tu, sach thu
ty nang » ky nang, ty xang, ty hang
cua tre » cua te, cuu tre, cua triet
ma hoi » mai hoi, ma hoa, me hoi

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

• Performing a fuzzy search may retrieve terms with similar spellings: doc sach ty nang ((ma hoi) OR (xa hoi)). lieu va ((tham tuc) or (thai tuc)) xac sinh dai cua tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: doc sach ty nang ((ma hoi) OR (xa hoi)). lieu va ((tham tuc) OR (thai tuc)) xac sinh dai cua tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "doc sach ty nang ((ma hoi) OR (xa hoi)). lieu va ((tham tuc) or (thai tuc)) xac sinh dai cua tre".
• Adding a wildcard symbol may retrieve word variants: doc sach ty nang ((ma hoi) OR (xa hoi)). lieu va ((tham tuc) or (thai tuc)) xac sinh dai cua tre*.