Perhaps you should try some spelling variations:
nam thuc » nam thuoc, am thuc, nam thu
cua viet » ca viet, hoa viet, cua vat
hieu van » hieu va, thien van, lieu va
vu sach » vu bach, su sach, vu khach
xa dung » xay dung, xa dong, va dung
cuu tre » cua tre, cau tren, cau treo
sach ty » sach y, sach tu, sach thu
cam tuc » cam xuc, cam tu, dam thuc
nang ma » tang ma, sang ma, nang cao
ty nang » ky nang, ty xang, ty hang
ma hoi » mai hoi, xa hoi, ma hoa

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

• Performing a fuzzy search may retrieve terms with similar spellings: vu sach ty nang ma hoi. hieu van ((cam tuc) or (nam thuc)) xa dung tai ((cua viet) or (cuu tre))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: vu sach ty nang ma hoi. hieu van ((cam tuc) OR (nam thuc)) xa dung tai ((cua viet) OR (cuu tre)).
• Adding a wildcard symbol may retrieve word variants: vu sach ty nang ma hoi. hieu van ((cam tuc) or (nam thuc)) xa dung tai ((cua viet) or (cuu tre))*.