Perhaps you should try some spelling variations:
vat thanh » dat thanh, gat thanh, tat thanh
vat hanh » van hanh, va hanh, nhat hanh
nam thuc » nam thuoc, am thuc, nam thu
dieu cua » dieu tra
sach tu » sach thu, cach tu, sach ty
su sach » so sach, vu sach
tu nano » truc nano
hieu va » lieu va, hieu qua
va nam » van nam, ha nam, va nay
nano x » nano 1, nano o
vi cua » vai cua, di cua
x hoi » xa hoi, o hoi, x ho

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

• Performing a fuzzy search may retrieve terms with similar spellings: su sach tu nano x hoi. hieu va nam thuc ((vat hanh) OR (vat thanh)) ((vi cua) or (dieu cua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach tu nano x hoi. hieu va nam thuc ((vat hanh) OR (vat thanh)) ((vi cua) OR (dieu cua)) tre*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach tu nano x hoi. hieu va nam thuc ((vat hanh) OR (vat thanh)) ((vi cua) or (dieu cua)) tre*".