Perhaps you should try some spelling variations:
thu sach » tu sach, thuat sach, thuoc sach
van hanh » van thanh, ban hanh, van anh
thuc van » thuc vat, thuc dan, thuc va
va tham » van tham, va cham, va thanh
nang xa » nang x, lang xa, mang xa
nang ma » tang ma, sang ma, nang cao
vi cua » vai cua, di cua
ve tai » te tai, de tai, le tai
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: thu sach y ((nang xa) OR (nang ma)) hoi. hieu ((ve tai) or (va tham)) thuc van hanh vi cua te~.
• If you are trying to use Boolean operators, they must be ALL CAPS: thu sach y ((nang xa) OR (nang ma)) hoi. hieu ((ve tai) OR (va tham)) thuc van hanh vi cua te.
• The words AND, OR and NOT may confuse the search; try adding quotes: "thu sach y ((nang xa) OR (nang ma)) hoi. hieu ((ve tai) or (va tham)) thuc van hanh vi cua te".
• Adding a wildcard symbol may retrieve word variants: thu sach y ((nang xa) OR (nang ma)) hoi. hieu ((ve tai) or (va tham)) thuc van hanh vi cua te*.