Perhaps you should try some spelling variations:
thu sach » thuat sach, thuoc sach, thu hoach
hieu van » hieu va, thien van, lieu va
va dinh » van dinh, va kinh, va tinh
van cam » van nam, van lam, van cau
cam lao » ca lao, cam lam, cam lo
tu sach » su sach, te sach, tu cach
y nang » ky nang, ly nang, v nang
lao va » tao va, cao va, bao va
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: ((thu sach) OR (tu sach)) y nang x hoi. hieu van cam lao va dinh ((vi luu) or (vi lua)) tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: ((thu sach) OR (tu sach)) y nang x hoi. hieu van cam lao va dinh ((vi luu) OR (vi lua)) tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((thu sach) OR (tu sach)) y nang x hoi. hieu van cam lao va dinh ((vi luu) or (vi lua)) tre".
• Adding a wildcard symbol may retrieve word variants: ((thu sach) OR (tu sach)) y nang x hoi. hieu van cam lao va dinh ((vi luu) or (vi lua)) tre*.