Perhaps you should try some spelling variations:
tham cung » thay cung, tham nhung, pham cong
van hanh » van thanh, ban hanh, van anh
tham cuu » cham cuu, thai cua, than cua
su sach » so sach, vu sach
hanh ki » hanh vi, hanh ky, hanh kien
hieu va » lieu va, hieu qua
lang xa » lang ha, dang xay, lang van
nang xa » nang x, nang ma, mang xa
su viet » so viet
sach v » sach va, sach y, sach 2
ki su » ky su

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 v ((nang xa) OR (lang xa)) hoi. hieu va ((tham cuu) OR (tham cung)) van hanh ki su viet~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach v ((nang xa) OR (lang xa)) hoi. hieu va ((tham cuu) OR (tham cung)) van hanh ki su viet".
• Adding a wildcard symbol may retrieve word variants: su sach v ((nang xa) OR (lang xa)) hoi. hieu va ((tham cuu) OR (tham cung)) van hanh ki su viet*.