Perhaps you should try some spelling variations:
hoc sach » hoc sinh, hoc cac, hoc anh
thuc van » thuc vat, thuc dan, thuc va
van quan » van ban
ky dang » ky nang, ky danh
van hoi » van hoa, van hoc, van hoe
ve phat » va phat, te phat, de phat
quan le » quang le, quan ly, quan li
y tang » ky tang, 6 tang, 7 tang
le cua » ly cua
cua te » cua tu
pham » phan

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

• Performing a fuzzy search may retrieve terms with similar spellings: hoc sach ((y tang) or (ky dang)) van hoi. hieu ((vi pham) or (ve phat)) thuc van quan le cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: hoc sach ((y tang) OR (ky dang)) van hoi. hieu ((vi pham) OR (ve phat)) thuc van quan le cua te.
• Adding a wildcard symbol may retrieve word variants: hoc sach ((y tang) or (ky dang)) van hoi. hieu ((vi pham) or (ve phat)) thuc van quan le cua te*.