Perhaps you should try some spelling variations:
nang khoa » hang khoa, dang khoa, nang hoa
toc sach » hoc sach, doc sach, thuoc sach
cham xuc » cam xuc, chat xuc, cham soc
khoa hoc » hoa hoc
hieu va » lieu va
sach ky » sac ky, sach y, sach ty
va tinh » may tinh
va danh » va dinh, va dan, va hanh
luu tre » luu tru, cuu tre, luy tre
vi luu » vi lua

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 nang khoa hoc. ((hieu va) OR (hieu qua)) cham xuc ((va tinh) or (va danh)) vi luu tre~.
• If you are trying to use Boolean operators, they must be ALL CAPS: toc sach ky nang khoa hoc. ((hieu va) OR (hieu qua)) cham xuc ((va tinh) OR (va danh)) vi luu tre.
• The words AND, OR and NOT may confuse the search; try adding quotes: "toc sach ky nang khoa hoc. ((hieu va) OR (hieu qua)) cham xuc ((va tinh) or (va danh)) vi luu tre".
• Adding a wildcard symbol may retrieve word variants: toc sach ky nang khoa hoc. ((hieu va) OR (hieu qua)) cham xuc ((va tinh) or (va danh)) vi luu tre*.