I still don't really see a shield. Again, the art is subjective. But, the fact that people are split on it is evidence for: (1) the writer never intending a shield, and people's pattern seeking brains are overactive; or (2) if there is a shield, the artist did a terrible job. I think the former is more likely.
Does this mean I think Thanos is an idiot for not using a shield against Odin? No, of course not. I'm sure there are numerous instances in comics where a character "forgets" to use his powers, even when its the most logical thing to use in that situation. This is the fault of the writer who opted not to have the character use that power. There's probably a million reasons why the writer didn't, maybe they forgot, lacked time, or its just plain bad writing. For example, Thor recently was knocked down by blasters in Avengers Assemble. Not once did he even attempt to try to block or absorb the blasts with his mjolnir. Apparently Thor forgot he could absorb energy with his hammer. Is Thor stupid? Nah, its Bendis being a crappy writer in that instance. But this is expected, because writers are humans, and hence fallible, and so are our pattern seeking brains.
I also think Thanos' personal shields can be just as powerful as his tech based shields. For example, when Thanos was blasted by the Omega (Galactus clone), he said the only reason he tanked it was because of his personal shields (and armour). Omega was said to be twice as powerful as Galactus.