Perhaps you should try some spelling variations:
cam truc » cau truc, lam truoc, nam truoc
nam truc » nam truoc, nam thuc, nam trung
toc sach » hoc sach, doc sach, thuoc sach
dang xay » dang van, van xay
hieu va » lieu va, hieu qua
xay hoi » xa hoi, tay hoi, cay phoi
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
ky dang » ky nang, ky danh
ket van » viet van, ket doan, kien van

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

• Performing a fuzzy search may retrieve terms with similar spellings: toc sach ky dang xay hoi. hieu va ((cam truc) OR (nam truc)) va tinh ((ket va) or (ket van)) trien~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky dang xay hoi. hieu va ((cam truc) OR (nam truc)) va tinh ((ket va) OR (ket van)) trien.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky dang xay hoi. hieu va ((cam truc) OR (nam truc)) va tinh ((ket va) or (ket van)) trien".
• Adding a wildcard symbol may retrieve word variants: toc sach ky dang xay hoi. hieu va ((cam truc) OR (nam truc)) va tinh ((ket va) or (ket van)) trien*.