Perhaps you should try some spelling variations:
nguoi sach » nguoi san, nuoc sach
hieu van » hieu va, thien van, lieu va
van nhan » van phan, van thanh, danh nhan
nhan loc » nhan luc, nhan hoc, nhan loai
tinh hai » tinh thai, trinh han, thanh hai
tinh bai » tinh bac, hinh bai, tinh bao
nang ma » tang ma, sang ma, nang cao
loc va » hoc va, luc va
y nang » ky nang, ly nang, v nang
ma hoi » mai hoi, xa hoi, ma hoa
ca tre » ca tren, cua tre, ca tru

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

• Performing a fuzzy search may retrieve terms with similar spellings: nguoi sach y nang ma hoi. hieu van nhan loc va ((tinh bai) or (((tinh hai) or (tinh chat)))) ca tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nguoi sach y nang ma hoi. hieu van nhan loc va ((tinh bai) OR (((tinh hai) OR (tinh chat)))) ca tre.
• Adding a wildcard symbol may retrieve word variants: nguoi sach y nang ma hoi. hieu van nhan loc va ((tinh bai) or (((tinh hai) or (tinh chat)))) ca tre*.