As the curtain closes on 2018, one thing is clear to investors: The stock market doesn't go up forever.

Over the past three months, the stock market has undergone its steepest correction since 2011, with the tech-heavy Nasdaq Composite entering bear market territory. A flurry of factors, including the trade war between the U.S. and China, political instability in the White House, the flattening of the yield curve, and the Fed choosing to raise rates, have increased the fear level among investors and sent the market to more than 14-month lows.

Yet what investors often overlook about the stock market is that it does, historically, rise over time. Even though stock market corrections happen, on average, every 1.86 years, the broader market has returned an average of 7% per year, inclusive of dividends and when adjusted for inflation. In other words, as long as you buy high-quality stocks and hold them for an extended period of time, you tend to come out a winner.

And make no mistake about it, this correction has led to plenty of bargains. The best stocks you can consider buying during the market correction just might be Celgene (NASDAQ:CELG), Whirlpool (NYSE:WHR), Amazon.com (NASDAQ:AMZN), and Philip Morris International (NYSE:PM).

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Image source: Getty Images.

Celgene

One of the more mind-boggling things that happens with market corrections is that the healthcare sector, and more specifically biotechnology companies, take a big hit. This might be understandable for money-losing drugmakers that have no approved products, but for a ridiculously profitable, high-margin company biotech like Celgene, this correction is a head-scratcher (but at the same time great if you're looking to buy or add).

The big knock against Celgene has always been the company's overreliance on multiple myeloma drug Revlimid, which makes up in the neighborhood of 60% of total sales. Although worries persist about generic competition, Celgene has reached settlements with these producers to keep most generic Revlimid off the market until the end of January 2026. This means Celgene has a long runway on which to grow a drug that should eventually top $10 billion in annual sales.

Celgene also has an abundant organic and partnered pipeline. New label indications for Revlimid and Otezla continue to drive growth, while Celgene's more than three dozen partners are working on cancer, inflammation, and immunology compounds that, in some instances, would represent first-in-class medicines. With Celgene standing firm on its guidance call for at least $12.50 in earnings per share in fiscal 2020, the stock looks to be a screaming bargain at the moment.

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Whirlpool

Brand-name companies with leading market share are usually worth a look, too, during market swoons. That's what makes appliance giant Whirlpool so intriguing.

As a cyclical company, investors have seen this before from Whirlpool. More recently, it's struggled as a result of the trade war between the U.S. and China. Steel and aluminum tariffs have increased its raw material costs, coercing the company to pass along higher prices to customers in its core North American market. Ultimately, this caused sale and profit projections for 2018 to decline modestly. But history shows us that price increases tend to be accepted by consumers within just a few quarters.

Meanwhile, Whirlpool has bolstered its presence in Asia, which has been by far its fastest-growing region in 2018, and in April announced a modified Dutch auction to repurchase up to $1 billion worth of its common stock. Remember, fewer shares outstanding can have a positive impact on earnings per share. Currently valued at a microscopic forward P/E of 6.6 -- the company's lowest in at least a decade -- and sporting a 4.2% yield, Whirlpool is becoming more attractive by the day.

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Image source: Amazon.com.

Amazon.com

Even though growth stocks are traditionally clobbered during corrections, much more than value stocks, you could argue that Amazon.com, which has shed more than a third of its market cap, is entering "value" territory.

Value is, of course, in the eye of the beholder. But Amazon's cash flow does a lot of talking -- and it's pretty convincing. Since Amazon loves to dip its toes into numerous ventures, I'd opine that cash flow per share, rather than earnings per share, is the appropriate measurement to determine how attractive a company like Amazon is to investors. Over the trailing five-year period, Amazon has been valued at an average of 30.4 times its cash flow. Yet, according to Wall Street's consensus 2021 prognostication, Amazon will earn $143 per share in cash flow. That'd place the company at a multiple of about 10, if its share price were static. That looks like a bargain.

Making the case even sweeter is the company's growing reliance on cloud platform Amazon Web Services (AWS). AWS supplies the bulk of Amazon's operating income ($2.08 billion in the most recent quarter), and AWS' operating margins have been steadily rising (now at 31%). This isn't to say Amazon is de-emphasizing its projects or e-commerce business, but it does go to show what a cloud powerhouse AWS has become. With little standing in Amazon's way, it looks like a solid bet for a long-term rebound.

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Image source: Getty Images.

Philip Morris International

Seeking out income potential in the declining market? As long as you have no socially responsible hang-ups, it could be time to nibble on Philip Morris International.

Don't get me wrong: I fully understand the negatives impacting the tobacco industry. On one hand, developed countries are waging war against the tobacco industry and the negative effects of smoking on the body. On the other hand, tobacco companies could soon face competition from the cannabis industry in legalized countries.

However, the tobacco industry does have incredible pricing power and innovation on its side. Philip Morris has been able to grow its top line thanks to the addictive nature of nicotine, and with the help of its IQOS heated tobacco device, which provides a perceived-to-be healthier alternative to smokable tobacco.

It's also overlooked, on occasion, that Philip Morris doesn't operate in the restrictive U.S. market. Rather, it has operations in more than 180 countries worldwide, giving it exposure to faster-growing emerging markets, which can help ebb weakness in developed markets. At less than 13 times forward earnings, and now carrying a 6.6% dividend yield, Philip Morris is a smoking-hot value and income stock.