@KK, It really helped!! Thank you!! Sorry for the obvious question, I should have known))

<cms:if frm_years!='-' >
<cms:set my_search_str="<cms:concat my_search_str ' | docyear==' frm_years />" scope='global'/>
</cms:if>
<cms:db_persist_form
_invalidate_cache='0'
_auto_title='1'
k_publish_date=frm_my_datetime
author=my_name
memberid=my_memberid
idfolder=my_page_id
/>
<div><!-- Start search snippet -->
<cms:embed 'document-report-filter.html' />
</div><!-- End search snippet -->
<div id="navigation-bar">
......
</div>
<div id="table"><!-- Start table -->
<table>
<tr>
<th>Date</th>
<th>Document name</th>
<th>Document type</th>
<th>Author</th>
</tr>
<cms:pages masterpage='members/documents.php' custom_field=my_search_str order='asc' paginate='1' limit='20'>
<cms:if k_paginated_top >
<cms:set my_records_found='1' scope='global'/>
<cms:if k_paginator_required >
Page <cms:show k_current_page /> of <cms:show k_total_pages /><br />
</cms:if>
</cms:if>
<cms:if excludreg >
... do something ....
<cms:else />
<tr>
<td><cms:date k_page_date format='d.m.Y' /></td>
<td><cms:show docname /></td>
<td><cms:show doctype /></td>
<td><cms:show author /></td>
</tr>
</cms:if>
</cms:pages>
</table>
</div><!-- End table -->
<cms:form name="quicksearch" id="quicksearch" anchor='0'>
<cms:if k_success >
<cms:if frm_years!='-' >
<cms:set my_search_str="<cms:concat my_search_str ' | docyear==' frm_years />" scope='global'/>
</cms:if>
<cms:if frm_doctypes!='-' >
<cms:set my_search_str="<cms:concat my_search_str ' | doctype==' frm_doctypes />" scope='global'/>
</cms:if>
<cms:if frm_authors!='-' >
<cms:set my_search_str="<cms:concat my_search_str ' | author==' frm_authors />" scope='global'/>
</cms:if>
</cms:if>
<div>
<label>Year:</label><br />
<cms:input type="dropdown"
opt_values="All=- | <cms:pages masterpage='members/years.php' order='asc'><cms:show year /><cms:if k_paginated_bottom='0' >|</cms:if></cms:pages>"
opt_selected='All'
name="years" id="years" />
</div>
<div>
<label>Document type:</label><br />
<cms:input type="dropdown"
opt_values="All=- | Internal | Incoming | Outgoing"
opt_selected='All'
name="doctypes" id="doctypes" />
</div>
<div>
<label>Author:</label><br />
<cms:input type="dropdown"
opt_values="All=- | <cms:pages masterpage='members/index.php' order='asc'><cms:show k_page_title /><cms:if k_paginated_bottom='0' >|</cms:if></cms:pages>"
opt_selected='All'
name="authors" id="authors" />
</div>
<br />
<div class="buttonset">
<cms:input type="submit" class="fbsubmitbtn" value="Generate report" name="submit"/>
</div>
</cms:form>