Perhaps you should try some spelling variations:
vat hanh » vat thanh, van hanh, va hanh
dieu cua » dieu tra
su sach » so sach, vu sach
sach tu » sach thu, cach tu, sach ty
tu nano » truc nano
nano x » nano 1, nano o
va nam » ha nam, va nay
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) OR (van nam)) thuc vat hanh ((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) OR (van nam)) thuc vat hanh ((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) OR (van nam)) thuc vat hanh ((vi cua) or (dieu cua)) tre*".