Multiple Table Joins Makes Query Go To Sleep

Hello All & Thanks in advance for your help!

Background:

1) tblT_Documents is the primary parent transaction table that has 10
fields and about 250,000 rows
2) There are 9 child tables with each having 3 fields each, their own
PK; the FK back to the parent table; and the unique data for that
table. There is a one to many relation between the parent and each of
the 9 child rows. Each child table has between 100,000 and 300,000
rows.
3) There are indexes on every field of the child tables (though I
don't believe that they are helping in this situation)
4) The client needs to be presented a view that has 5 of the main
fields from the parent table, along with any and all corresponding
data from the child tables.
5) The client will select this view by doing some pattern-matching
search on one of the child records' detail (e.g. field-name LIKE
%search-item% - so much for the indexes...)

Problem:

When I do the simple join of just the parent with one of the children,
the search works *fairly* well and returns the five parent fields and
the corresponding matching child field.

However, as soon as I add any one of the other child records to simply
display it's unique data along with the previously obtained results,
the resulting query hangs.

Is the overall structure of the tables not conducive to this kind of
query? Is this a situation where de-normalization will be required to
obtain the desired results? Or, more hopefully, am I just an idiot
and there is some simpler solution to this problem?!

Thanks again for your assistance!

- Ed