Normally, you do not have to use a different search strategy from the one detailed in the box to the left for SOLO to find most e-books available in the Bodleian.
However, holders of an Oxford Single Sign on should independently open & check in both LexisLibrary (via the Sources Link)
AND Westlaw UK (via the Commentary link) to see what these databases include that could support your studies.
Both services will have (different) collections of important texts & reference works for the legal practictioner.
Subject searches to try in SOLO to find tax law titles include
Taxation - law and legislation
Income tax - law and legislation
Corporations -- Taxation -- Law and legislation
The name of a particular jurisdiction can added eg - Great Britain - so that the results are filtered.
Of course it is also possible to see if there are titles just dealing with a more narrow aspect of tax law. Some examples are:
Capital gains tax - Law and legislation
Charitable uses, trusts, and foundations -- Taxation
Gifts -- Taxation
Inheritance and transfer tax - Law and legislation
International business enterprises -- Taxation -- Law and legislation
Investments - Taxation - Law and legislation
Investments, Foreign - Taxation - Law and legislation
Tax administration and procedure
Tax shelters - Law and legislation
Value added tax - Law and legislation
Conversely, to find titles looking more at policy try
Taxation and/or Fiscal policy (with or without Great Britain etc as above. )
and/or remove the "law and legislation" element from your subject search & run it again.
As tax law is a taught subject, look out for the phrase "Bodleian Law Library Reserve Collection" as a location in results of searches in SOLO.
If you see it, the book is available (provided no-one else has got there first!) from the special Reserve Collection desk (near the library exit). Armed with your University Card or Reader's Ticket, ask a member of staff for the book.
If you are looking for a tax title on your Reading List, it may have the location Bodleian Law Library Reserve Collection .... like the following!
Ask for these at the Enquiry Desk on Floor 2.