I am searching for oracle admin tool like SQL Buddy (here). Among the finest to make use of the browser to check my querys.
Just for to check querys you can test iSQL (but it's deprecated in 11g) or might be turn to http://www.oracletool.com/
You could attempt using APEX. It is not particularly an admin tool (more for energy-customers/designers), but it's built-in on more recent databases. You are able to write SQLs, build packages and methods, view and filter data, etc.
Whilst not internet based I recommend Oracle's (free) Sql Developer http://www.oracle.com/technetwork/developer-tools/sql-developer/downloads/index.html or (also free/OSS) Squirrel: http://squirrel-sql.sourceforge.net/
The very best for me personally is SQLTool (http://www.sqltools.internet/), it´s free, faster, simple to use and provides extensive option.