Perhaps you should try some spelling variations:
su sach » so sach, vu sach
va tich » va tinh, va dich
thuc va » thuc vat, thuc dan, thuc day
sach ky » sac ky, sach y, sach ty
sang ma » tang ma, nang ma, sang tao
nang xa » nang x, lang xa, nang ma
ve hoc » va hoc, vi hoc, de hoc
va cua » va chua, via cua, ca cua
cua te » cua tu

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 ((nang xa) or (sang ma)) hoi. hieu ((ve hoc) OR (te hoc)) thuc va tich va cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: su sach ky ((nang xa) OR (sang ma)) hoi. hieu ((ve hoc) OR (te hoc)) thuc va tich va cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "su sach ky ((nang xa) or (sang ma)) hoi. hieu ((ve hoc) OR (te hoc)) thuc va tich va cua te".
• Adding a wildcard symbol may retrieve word variants: su sach ky ((nang xa) or (sang ma)) hoi. hieu ((ve hoc) OR (te hoc)) thuc va tich va cua te*.