Perhaps you should try some spelling variations:
nam trung » nam trong, tai trung, ba trung
nam truc » nam truoc, nam thuc, nam thuoc
su sach » so sach, vu sach
va hanh » van hanh, va thanh, va danh
cuu tre » cua tre, cau tren, cau treo
hieu va » lieu va, hieu qua
mai hoi » mai khoi, dai hoi, lai hoi
ky sang » ky dang, ky tang, duy sang
vi cuu » vi luu, vinh cuu

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 ((ky sang) or (ky nang)) mai hoi. hieu va ((nam truc) OR (nam trung)) va hanh vi cuu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ((ky sang) OR (ky nang)) mai hoi. hieu va ((nam truc) OR (nam trung)) va hanh vi cuu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ((ky sang) or (ky nang)) mai hoi. hieu va ((nam truc) OR (nam trung)) va hanh vi cuu tre".
• Adding a wildcard symbol may retrieve word variants: su sach ((ky sang) or (ky nang)) mai hoi. hieu va ((nam truc) OR (nam trung)) va hanh vi cuu tre*.