When searching using parentheses (aka "nesting") you must use a Boolean operator. If a Boolean operator is not included, the search engine cannot determine which operation to process first, causing the search to fail.
If you want to search for an exact phrase that includes parentheses, you should enclose your entire phrase in quotation marks. For example, to search for the following phrase:
English (Second Language)
Enter the following in the Find field:
“English (Second Language)”