ciao, sei Italiano?
prova cosi, mi sembra che funzioni
<?php if( osc_is_home_page() || osc_is_publish_page() ) { } else { ?>
<form action="<?php echo osc_base_url(true); ?>" method="get" class="search nocsrf" <?php /* onsubmit="javascript:return doSearch();"*/ ?>>
<input type="hidden" name="page" value="search"/>
<div class="main-search">
<div class="cell">
<input type="text" name="sPattern" id="query" class="input-text" value="" placeholder="<?php echo osc_esc_html(__(osc_get_preference('keyword_placeholder', 'bender_theme'), 'bender')); ?>" />
</div>
<?php if ( osc_count_categories() ) { ?>
<div class="cell selector">
<?php osc_categories_select('sCategory', null, __('In tutte le categorie', 'bender')) ; ?>
</div>
<div class="cell reset-padding">
<?php } else { ?>
<div class="cell">
<?php } ?>
<button class="ui-button ui-button-big js-submit"><?php _e("Search", 'bender');?></button>
</div>
</div>
<div id="message-seach"></div>
</form>
<?php } ?>
EDIT:
anche con questo dovrebbe funzionare
<?php if( (!osc_is_home_page()) && (!osc_is_publish_page()) ) { ?>