Perhaps you should try some spelling variations:
thuat sach » thuat lanh, thuat san
tang mai » tang ma, tang tai, lang mai
tinh ven » trinh ven, tinh yen, sinh vien
tinh ve » trinh ve, dinh ve, tinh va
nam tuc » nam thuc, nam truc, nam tu
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
cuu tre » cua tre, cau tren, cau treo
va nam » van nam, ha nam, va nay
y tang » ky tang, 6 tang, 7 tang
cua tu » cua tuc, cua su, cua cu

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

• Performing a fuzzy search may retrieve terms with similar spellings: thuat sach y tang mai hoi. hieu va nam tuc xa ((tinh ve) OR (tinh ven)) ((cua tu) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thuat sach y tang mai hoi. hieu va nam tuc xa ((tinh ve) OR (tinh ven)) ((cua tu) OR (cuu tre)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "thuat sach y tang mai hoi. hieu va nam tuc xa ((tinh ve) OR (tinh ven)) ((cua tu) or (cuu tre))".
• Adding a wildcard symbol may retrieve word variants: thuat sach y tang mai hoi. hieu va nam tuc xa ((tinh ve) OR (tinh ven)) ((cua tu) or (cuu tre))*.