Perhaps you should try some spelling variations:
doanh vien » doanh tien, doanh chien, thanh vien
danh dien » dinh dien, danh kien, danh lien
thu sach » tu sach, thuat sach, thuoc sach
hieu van » hieu va, thien van, lieu va
hau truc » cau truc, hang truc, hoc truc
truc va » thuc va, thuc vat, trung va
van hau » van ha, van hai, van dau
nang ma » tang ma, sang ma, nang cao
cu tren » tu tren, dua tren
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
cu tre » cua tre, cuu tre, cu tri

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

• Performing a fuzzy search may retrieve terms with similar spellings: thu sach y nang ma hoi. hieu van hau truc va ((danh dien) or (doanh vien)) ((cu tre) or (cu tren))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y nang ma hoi. hieu van hau truc va ((danh dien) OR (doanh vien)) ((cu tre) OR (cu tren)).
• Adding a wildcard symbol may retrieve word variants: thu sach y nang ma hoi. hieu van hau truc va ((danh dien) or (doanh vien)) ((cu tre) or (cu tren))*.